Solve linear and quadratic equations. Enter coefficients to find roots instantly.
Quadratic equation: ax² + bx + c = 0
Roots
x₁ = 2 x₂ = 1
Two distinct real roots.
Discriminant1
Sum of roots3
Product of roots2
Quadratic equations must have a non-zero coefficient a. Complex roots appear as a ± bi.
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What is the Equation Solver?
An equation solver is a mathematical tool that finds the value(s) of unknown variables (usually x or y) that make an equation true. For example, in the equation 2x + 5 = 15, the solver determines that x = 5 because 2(5) + 5 = 15. It works with linear equations (first-degree), quadratic equations (second-degree), and higher-order polynomials.
How it works
The solver rearranges the equation to isolate the variable step by step. For linear equations, it moves constants to one side and variables to the other, then divides by the coefficient. For quadratic equations (ax² + bx + c = 0), it applies the quadratic formula or factors the expression. The tool displays each step so you understand not just the answer, but the method used to find it.
Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a
For any quadratic equation ax² + bx + c = 0, substitute the coefficients a, b, and c into this formula. The ± symbol means there are usually two solutions (roots) for a quadratic equation. The expression under the square root (b² - 4ac) is called the discriminant and tells you how many real solutions exist.
Examples
Input
Result
Notes
Linear: 3x + 7 = 22
x = 5
Subtract 7 from both sides to get 3x = 15, then divide by 3.
Quadratic: x² - 5x + 6 = 0
x = 2 or x = 3
Factors as (x - 2)(x - 3) = 0, so both 2 and 3 satisfy the equation.
Two-variable: 2x + 3y = 12 with y = 2
x = 3
Substitute y = 2 to get 2x + 6 = 12, then solve for x.
How to use the Equation Solver
Enter your equation (e.g., 2x + 5 = 15) in the input field
Specify the variable you want to solve for (usually x, but can be any letter)
Click 'Solve' to process the equation
Review the step-by-step solution showing each transformation
Check the final answer and verify by substituting it back into the original equation
Copy the solution or use it for further calculations
Benefits
Saves time on homework and test prep by solving equations instantly
Shows step-by-step working, so you learn the method, not just the answer
Handles multiple equation types: linear, quadratic, polynomial, and systems
Catches algebra mistakes before they compound in bigger problems
Free and ad-light, no sign-up required to start solving
Useful for professionals checking calculations in engineering, finance, and science
Tips & common mistakes
Common mistakes
Forgetting to apply the same operation to both sides of the equation (violates the golden rule of algebra)
Mishandling negative signs when moving terms across the equals sign
Assuming a quadratic equation has exactly one solution (many have two, some have none)
Entering the equation in the wrong format or with ambiguous spacing
Tips
Always verify your answer by substituting it back into the original equation — if it makes the equation true, you're correct
For complex equations, break them down into smaller steps and solve one operation at a time
Remember that quadratic equations can have zero, one, or two real solutions depending on the discriminant
Use parentheses generously when entering equations to avoid misinterpretation of order of operations
Frequently asked questions
Can this solver handle equations with fractions and decimals?
Yes. Enter them as they are (e.g., 0.5x + 2 = 7 or x/4 + 3 = 5). The solver will work with both.
What's the difference between solving linear and quadratic equations?
Linear equations have one solution and involve variables with exponent 1. Quadratic equations involve variables squared (exponent 2) and typically have two solutions. The solver uses different methods for each.
Why does my quadratic equation show 'no real solutions'?
This means the discriminant (b² - 4ac) is negative, so there are no real-number answers — only complex numbers. This happens when the parabola doesn't cross the x-axis.
Can I solve equations with multiple variables?
Yes, if you specify which variable to solve for. For example, in 2x + 3y = 12, you can solve for x in terms of y, or vice versa.
Is this tool suitable for teaching algebra?
Absolutely. The step-by-step breakdown helps students understand the process, not just memorize answers. Teachers often use such tools to check work and explain methods.
What types of equations can't this solver handle?
Very advanced equations like trigonometric, exponential, or transcendental equations may require specialist tools, though basic versions might work here.