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x Algebra Calculator

Two tools in one: evaluate any algebraic expression by substituting a value for x, or solve a linear equation of the form ax + b = c instantly with full step-by-step workings.

Section 1 — Expression Evaluator

Enter an expression using x as the variable (e.g. 2*x^2 + 3*x - 1), then provide the value of x.

Section 2 — Linear Equation Solver

Solve equations in the form ax + b = c. Enter the coefficients below.

x +
=

General Solution Formula

Linear equation: ax + b = c  →  x = (c − b) / a
Expression eval: f(x) = 2x² + 3x − 1 at x=2 → 2(4) + 3(2) − 1 = 13

Example — Solving 3x + 7 = 22

Given: 3x + 7 = 22  (a=3, b=7, c=22)
Step 1: Subtract b from both sides: 3x = 22 − 7 = 15
Step 2: Divide by a: x = 15 ÷ 3
Solution: x = 5
Check: 3(5) + 7 = 15 + 7 = 22 ✓

Frequently Asked Questions

Algebra is a branch of mathematics that uses symbols (usually letters like x) to represent unknown values. It provides rules for manipulating these symbols to solve equations and understand relationships between quantities.

To solve ax + b = c for x: first subtract b from both sides to get ax = c − b, then divide both sides by a to get x = (c − b) / a. Always verify by substituting x back into the original equation.

PEMDAS / BODMAS: Parentheses (Brackets), Exponents (Orders), Multiplication and Division (left to right), Addition and Subtraction (left to right). The expression calculator follows this order automatically.

FOIL stands for First, Outer, Inner, Last — a method for multiplying two binomials. (a+b)(c+d) = ac + ad + bc + bd. For example, (x+2)(x+3) = x² + 3x + 2x + 6 = x² + 5x + 6.

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