Linear Equation Calculator
Enter a, b, c and d for ax + b = cx + d.
This result is an estimate only. Double-check important figures before relying on them.
How it is calculated
- x = (d − b) ÷ (a − c)
- If a = c and b = d, every x works
- If a = c and b ≠ d, there is no solution
For equations with x squared, use the quadratic equation calculator.
Worked example
3x + 5 = x + 11:
- x = (11 − 5) ÷ (3 − 1) = 3
- Left side 14, right side 14
Why your number may differ
Only equations with x to the first power fit this form. Equations with fractions need clearing first.
Frequently asked questions
How do I solve ax + b = cx + d?
Move the x terms to one side and the numbers to the other: x = (d − b) ÷ (a − c).
When is there no solution?
When a = c but b ≠ d. The two lines are parallel and never meet.
How do I check the answer?
Put x back into both sides. They should give the same number, as shown in the result.