Solving one- and two-step equations

An equation is a balance: whatever you do to one side, you do to the other. To solve for x, you undo the operations around it — in reverse order.

One step

x + 7 = 12. The inverse of "+ 7" is "− 7", so subtract 7 from both sides: x = 5.

Two steps

2x + 3 = 11. Undo in the reverse of the order of operations — the + 3 first, then the × 2:

• subtract 3 from both sides: 2x = 8
• divide both sides by 2: x = 4

That's the whole engine of algebra: isolate the variable by undoing what's been done to it. The pre-algebra solver shows these steps for any ax + b = c.