Do the same to both sides
An equation is a balance. Whatever you do to one side, do to the other, and undo the operations in reverse order.
- 5x + 7 = 32
- subtract 7: 5x = 25
- divide by 5: x = 5
- check: 5 × 5 + 7 = 32
Negatives and fractions are fine
- 12 − 3x = 18: subtract 12, so −3x = 6, and x = −2.
- 4x − 1 = 6: 4x = 7, so x = 7/4 (or 1.75). Leave it exact rather than rounding.
- x/3 + 2 = 9: x/3 = 7, so x = 21.
With a bracket, either divide first or expand first: 3(x + 4) = 21 gives x + 4 = 7, so x = 3.
Compare with the solver
Choose Linear and enter 5x + 7 = 32. Read each line of its working and match it to a step above. Then try 12 − 3x = 18.