Math

Linear Equation Calculator

Solve a linear equation with x on both sides and see each rearrangement, an exact fractional answer and a substitution check.

TRY A WORKED EXAMPLE

Choose a starting point, adjust the values, then calculate.

Use whole-number coefficients from −10,000 to 10,000. The equation format is shown in the input labels.
01

Your inputs

02

Your result

Ready when you are.

Adjust the inputs, then calculate to see your result here.

Calculated on your device.

GET MORE FROM YOUR RESULT

Using the Linear Equation Calculator

Use this when unknown quantities appear once to the first power. Enter the coefficients of ax + b = cx + d; a negative constant needs its minus sign. This tool accepts whole-number coefficients, rather than arbitrary typed expressions.

Worked example

Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.

Example inputs

a · x (left)
3
b (left constant)
5
c · x (right)
1
d (right constant)
13

Example result

Solution
x = 4
Decimal approximation
4
Verification
Left side = right side = 17
Steps
Start with 3x + (5) = 1x + (13). Subtract 1x and 5 from both sides: 2x = 8. Divide both sides by 2: x = 4. Substitute into the original equation; left and right sides agree (rounding may affect the decimal display).

Method and assumptions

Collect x terms on one side and constants on the other, then divide. Integer coefficients from −10,000 to 10,000; exact fraction results. Identical and contradictory equations are handled separately.

Reference: openstax.org — method and further reading

Check the answer in the original problem

After solving, substitute the result into the original equation or relationship where possible. This can catch a sign error or a coefficient entered in the wrong position. Keep the exact inputs available when comparing with another tool, since changing a coefficient or rounding an intermediate value can change the problem being solved.

Common question

Why does my equation have no single answer?

When both sides simplify to the same expression, every real x works. If they simplify to different constants, no value of x can make the equation true.