Linear Equation Solver
Solve equations of the form ax + b = c for x
About this calculator
A linear equation has the form ax + b = c, where x is the unknown. To solve: subtract b from both sides to get ax = c − b, then divide by a to get x = (c − b) / a. For 3x + 5 = 14: x = (14 − 5) / 3 = 3. Linear equations model countless real-world situations: costs, distances, time, and rates.
How to use
If you earn 3 kr per item plus a 5 kr base fee, and you received 14 kr total, how many items did you sell? a=3, b=5, c=14 → x = 3 items.
Frequently asked questions
What if a equals zero?
If a = 0, the equation becomes b = c. Either there are no solutions (if b ≠ c) or infinitely many solutions (if b = c), because x can be anything.
What makes an equation 'linear'?
The variable x appears only to the first power — no x², no √x, no 1/x. The graph of a linear equation is always a straight line, hence the name.