A linear equation has one unknown to the first power. It always has exactly one solution unless a = 0.
How to use the Linear Equation Solver
- a
- b
- c
Results update as you type, and every field accepts the units shown in its menu.
How it works
Subtract b from both sides, then divide by a.
Inputs explained
| Field | What to enter |
|---|---|
| a | A number |
| b | A number |
| c | A number |
Example values
How the main result changes when a changes and everything else stays at the example values above:
| a | x |
|---|---|
| 2 | 14 |
| 3 | 9.3333 |
| 4 | 7 |
| 5 | 5.6 |
| 6 | 4.6667 |
| 8 | 3.5 |
Formula
x = (c − b) ÷ aWorked example
Inputs — a: 4; b: -7; c: 21.
Results — x = 7; Check: a·x + b = 21.
Frequently asked questions
What if a = 0?
There is no solution unless b = c, in which case every x works.
How do I solve 3(x + 2) = 15?
Expand to 3x + 6 = 15, so a = 3, b = 6, c = 15.
What formula does the Linear Equation Solver use?
x = (c − b) ÷ a.