Math calculators

Algebra Calculator

Updated Sep 23, 2026 By Infinity Calculator
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Enter Your Problem
Accepted syntax: + - * / ^ , sqrt(x), abs(x) or |x|, pi, @ for substitution (2x+y @ x=3, y=1), commas for systems (x+y=5, x-y=1).
Detected: —
Example problems
Choose an Operation
Combines like terms, clears brackets and reduces fractions.
Applies the distributive property, FOIL and binomial expansion.
Pulls out the GCF, then factors completely over the rationals.
Variable values (up to 4 detected)
Use <, >, <= or >= . Compound form supported, e.g. 1 < 2x+3 < 9.
ResultSolve
Step-by-Step Solution
Graph Preview
Check Your Answer

Introduction

This algebra calculator solves math problems and shows you every step. Type a problem like 4x+2=2(x+6) or x^2-5x+6=0, then press Calculate. You get the answer, the steps, and a graph.

You can do a lot with it:

  • Solve equations for x, including quadratics with real or complex answers
  • Simplify and expand expressions, or factor them
  • Evaluate an expression when you know the values of the variables
  • Inequalities with <, >, ≤, and ≥, shown on a number line
  • Systems of equations using elimination, substitution, or Cramer's Rule
  • Graph your equation and see where it crosses the axes

There is also a "More Actions" menu for things like degree, intercepts, vertex, domain, and the discriminant. If you are not sure how to type a symbol, open the keypad and tap it. Want to check your own work? Type your answer in the "Check Your Answer" box and the tool will tell you if it matches.

Use it for homework, test review, or just to see how a problem works step by step.

How to use our Algebra Calculator

Type an algebra problem, pick what you want done with it, and the calculator shows the answer, step-by-step work, a graph, and a number line.

Expression or equation: Type your problem here, like 4x+2=2(x+6) or x^2-9. Use + - * / ^ , sqrt(x) for square roots, |x| for absolute value, and commas to list more than one equation. The preview under the box shows how your problem looks in math form.

Clear button (×): Press the × inside the box to erase what you typed and start again.

New Problem: Clears the input and all past results so you can enter a fresh question.

Show Keypad: Opens buttons for numbers, x, y, z, powers, roots, fractions, and signs. Tap "Full Pad" for extras like ≤, ≥, ln, and log.

Example problems: Click any example chip to drop that problem into the box. Click "Show More Examples" for a longer list.

Quick action buttons: Tap Simplify, Solve for x, Expand, Factor, Evaluate, or Graph to run that job right away. "More Actions" adds degree, leading coefficient, intercepts, vertex, completing the square, domain, and discriminant.

Tabs: Pick the tab that matches your job: Solve, Solve for Variable, Simplify, Expand, Factor, Evaluate, Inequalities, Systems, or Graph.

Include complex solutions (Solve tab): Leave this checked to see imaginary answers with i. Uncheck it to see only real answers.

Solve for (Solve for Variable tab): Choose which letter to get by itself, such as y in ax+by=c.

Variable values (Evaluate tab): Type a number for each letter the calculator finds, like x = 5 and y = 3. You can also write values after an @ sign in the main box.

Show variable sliders: Check this to drag a slider for each letter and watch the answer change as you move it.

Method (Systems tab): Choose Elimination, Substitution, or Cramer's Rule to see the steps solved that way.

X min, X max, Y min, Y max (Graph tab): Set how far the graph goes left, right, down, and up, then press "Redraw Graph".

Calculate: Press this to get your answer and the full step-by-step solution.

Reset: Puts the calculator back to its starting problem and settings.

Answer form: Switch between exact, decimal, factored, or interval forms of the answer, then press "Copy Result" to save it.

Check Your Answer: Type your own answer, like x=2, x=3, and press Verify to see if it matches the solution.

What Is Algebra?

Algebra is math that uses letters, like x or y, to stand for numbers you do not know yet. Those letters are called variables. Your job is to find what number the letter stands for, or to write the math in a simpler way.

Key Words to Know

  • Term: one piece of a math problem, like 3x or 7.
  • Coefficient: the number in front of a variable. In 5x, the 5 is the coefficient.
  • Expression: math with no equals sign, like 2x + 4.
  • Equation: math with an equals sign, like 2x + 4 = 10.
  • Inequality: math that uses <, >, ≤, or ≥ instead of equals.
  • Like terms: terms with the same letter and power, like 3x and 5x. You can add them.

Common Algebra Jobs

Solve means find the value of the variable. Keep the equation balanced: whatever you do to one side, do to the other side too.

Simplify means make it shorter by adding like terms and cutting extra brackets.

Expand means multiply things out. For example, 2(x + 3) becomes 2x + 6. This uses the distributive property.

Factor is the opposite of expand. You break the math into parts that multiply together, like x² − 5x + 6 = (x − 2)(x − 3).

Evaluate means put in a number for each letter and work out the answer.

Types of Equations

  • Linear: the highest power is 1, like 4x + 2 = 10. Its graph is a straight line. It has one answer.
  • Quadratic: has an , like x² − 5x + 6 = 0. Its graph is a U shape called a parabola. It can have two answers, one answer, or no real answers.
  • Cubic and higher: has or more. It can have more answers.
  • System: two or more equations at once, like x + y = 5 and x − y = 1. The answer is the point where the lines cross.

The Quadratic Formula

For any equation shaped like ax² + bx + c = 0, the answers are x = (−b ± √(b² − 4ac)) / 2a. The part under the square root, b² − 4ac, is called the discriminant. If it is positive, there are two real answers. If it is zero, there is one. If it is negative, the answers are imaginary numbers.

Order of Operations

Always work in this order: parentheses, exponents, multiply and divide (left to right), then add and subtract (left to right). People remember it as PEMDAS.

Tips That Help

  • Check your answer by putting it back into the first equation. Both sides should match.
  • When you multiply or divide an inequality by a negative number, flip the sign.
  • A fraction can never have zero on the bottom. Toss out any answer that makes the bottom zero.
  • Do one step at a time and write each step down. It makes mistakes easy to spot.

Why Algebra Matters

Algebra helps you solve real problems: working out a budget, finding a missing measurement, comparing phone plans, or changing a recipe. It is also the base for geometry, trigonometry, science, coding, and money math later on.


Formulas used

Linear equation solution
ax+b=0 \;\Rightarrow\; x=-\frac{b}{a}
Quadratic formula
x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}
Discriminant
\Delta=b^2-4ac
Vertex and axis of symmetry of a parabola
x=-\frac{b}{2a},\qquad \left(-\frac{b}{2a},\; f\!\left(-\frac{b}{2a}\right)\right)
Completing the square (vertex form)
ax^2+bx+c=a\left(x+\frac{b}{2a}\right)^2+\left(c-\frac{b^2}{4a}\right)
Difference of squares factoring
a^2-b^2=(a-b)(a+b)
Cramer's rule for a linear system
x_j=\frac{D_j}{D},\qquad D=\det(A),\; D_j=\det(A_j)
Rational expression combination (addition of fractions)
\frac{a}{b}+\frac{c}{d}=\frac{ad+cb}{bd}

Frequently asked questions

How do you solve an equation with x on both sides?

Get all the x terms on one side and all the plain numbers on the other side.

  1. Multiply out any brackets: 4x + 2 = 2(x + 6) becomes 4x + 2 = 2x + 12.
  2. Subtract 2x from both sides: 2x + 2 = 12.
  3. Subtract 2 from both sides: 2x = 10.
  4. Divide both sides by 2: x = 5.

Put 5 back in the first equation to check. Both sides give 22.

What does FOIL mean in algebra?

FOIL is a way to multiply two brackets. It stands for First, Outer, Inner, Last.

For (x + 2)(x + 3):

  • First: x × x = x²
  • Outer: x × 3 = 3x
  • Inner: 2 × x = 2x
  • Last: 2 × 3 = 6

Add them up and combine like terms: x² + 5x + 6.

What is an extraneous solution?

An extraneous solution is an answer that shows up in your work but does not actually work in the original problem.

They happen most with square roots and fractions. For sqrt(3 + x) = -2, squaring both sides gives x = 1. But sqrt(4) = 2, not -2, so x = 1 is extraneous and the equation has no solution.

Always plug your answers back into the first line. Toss out any that make a denominator zero or a square root equal a negative.

Why do you flip the inequality sign when you multiply by a negative?

Because negative numbers reverse the order of the number line. 2 is less than 5, but -2 is greater than -5.

So when you multiply or divide both sides by a negative number, the sign must flip to stay true.

Example: -x > 3 becomes x < -3 after dividing by -1.

Adding or subtracting a negative does not flip the sign.

What does the i mean in an answer like x = 2 + 3i?

The letter i stands for the square root of -1. It is called an imaginary number.

No real number times itself gives a negative, so math uses i to write those answers. You see i when the discriminant (b² - 4ac) is negative.

An answer like 2 + 3i is a complex number. It does not show up as a crossing point on a graph, because the curve never touches the x-axis.

How do you find the vertex of a parabola?

For y = ax² + bx + c, use x = -b / (2a). That gives the x-value of the vertex. Then put that number back in to get y.

Example: y = x² - 6x + 5. Here a = 1 and b = -6, so x = 6 / 2 = 3. Then y = 9 - 18 + 5 = -4. The vertex is (3, -4).

The axis of symmetry is the vertical line through the vertex: x = 3.

How do you complete the square?

Completing the square turns x² + bx + c into a perfect square plus a number.

  1. If there is a number in front of x², factor it out first.
  2. Take half of b, then square it.
  3. Add that value and subtract it, so nothing changes.
  4. Write the first three terms as a square.

Example: x² + 6x + 2. Half of 6 is 3, and 3² = 9. So x² + 6x + 9 - 9 + 2 = (x + 3)² - 7.

How do you find the domain of a rational expression?

The domain is every number you are allowed to put in. For a fraction, that is all real numbers except the ones that make the bottom zero.

Set the denominator equal to zero and solve. Those answers are not allowed.

Example: for (x + 3) / (x - 2), set x - 2 = 0, so x = 2 is banned. The domain is all real numbers with x ≠ 2.

What is the rational root theorem?

It gives you a short list of fractions to test as roots of a polynomial.

Every rational root has the form p / q, where p is a factor of the constant term and q is a factor of the leading coefficient.

For x³ + 6x² + 11x + 6, the constant is 6 and the leading coefficient is 1. So try ±1, ±2, ±3, ±6. Plug each in; the ones that give zero are roots. Here they are -1, -2, and -3.

How do you factor a quadratic like x² − 5x + 6?

Find two numbers that multiply to the last term and add to the middle number.

For x² - 5x + 6, you need two numbers that multiply to 6 and add to -5. Those are -2 and -3.

So it factors as (x - 2)(x - 3).

If the x² term has a number in front, pull out any common factor first, or use the quadratic formula instead.

What is a difference of squares?

It is a pattern where one perfect square is subtracted from another. It always factors the same way:

a² - b² = (a - b)(a + b)

Examples: x² - 9 = (x - 3)(x + 3), and 9x² - 25 = (3x - 5)(3x + 5).

This only works with a minus sign. A sum like x² + 9 does not factor with real numbers.

What is the difference between elimination and substitution?

Both solve systems of equations, just in different ways.

  • Elimination: add or subtract the two equations so one variable cancels out. Best when the x or y terms already match or are easy to match.
  • Substitution: solve one equation for a single variable, then put that into the other equation. Best when a variable is already alone, like y = 2x + 1.

Both give the same answer, so pick the one that looks easier.

What is Cramer's rule?

Cramer's rule solves a system using determinants. For two equations with x and y, you find D (the determinant of the coefficients), then Dx and Dy by swapping in the answer column.

Then x = Dx / D and y = Dy / D.

It only works when the number of equations matches the number of variables and D is not zero. If D = 0, the system has no single answer, so use elimination instead.

What does it mean when an equation has no solution or infinitely many solutions?

Watch what happens when the variables cancel out.

  • If you end with a false statement like 3 = 7, there is no solution. No number works.
  • If you end with a true statement like 0 = 0, there are infinitely many solutions. Every number works. This is called an identity.

For two lines, no solution means the lines are parallel. Infinitely many means they are the same line.

How do you solve an absolute value equation?

Absolute value means distance from zero, so the inside can be positive or negative. Split it into two equations.

For |2x - 4| = 6:

  • 2x - 4 = 6, so x = 5
  • 2x - 4 = -6, so x = -1

Both answers work. But if the absolute value equals a negative number, like |x| = -3, there is no solution, because distance is never negative.

What is interval notation?

Interval notation is a short way to write a range of numbers.

  • Square brackets [ ] mean the end number is included (≤ or ≥).
  • Parentheses ( ) mean it is not included (< or >).
  • Infinity always gets a parenthesis, since you never reach it.
  • The symbol joins two separate pieces.

Example: x > 2 is written (2, ∞). And x ≤ -1 or x ≥ 3 is written (-∞, -1] ∪ [3, ∞).

How do you get rid of fractions in an equation?

Multiply every term on both sides by the lowest common denominator.

Example: x/2 + 1/3 = 5/6. The LCD is 6. Multiply everything by 6 to get 3x + 2 = 5, so x = 1.

If the variable is on the bottom, do the same thing, then check your answers. Any answer that makes a denominator zero must be thrown out.

What is the degree of a polynomial and why does it matter?

The degree is the highest exponent in the expression. In 3x³ - 5x + 1, the degree is 3. If a term has more than one letter, add the exponents in that term.

The degree tells you the most solutions an equation can have. A degree 2 equation has at most 2 answers, degree 3 has at most 3, and so on. It also tells you the shape: degree 1 is a straight line, degree 2 is a U-shaped parabola.