⚙ Two-Step Equations

Two Operations, Two Steps

Two-step equations look like ax + b = c. There are two operations applied to x — multiplication by a and addition of b. To undo them, work in reverse order: first undo the addition/subtraction, then undo the multiplication/division.

Solving 3x + 7 = 22

1. Subtract 7 from both sides: 3x + 7 − 7 = 22 − 7 → 3x = 15
2. Divide both sides by 3: 3x/3 = 15/3 → x = 5
3. Check: 3(5) + 7 = 15 + 7 = 22 ✓

Why This Order?

Order of operations (PEMDAS) tells us multiplication happens before addition when evaluating. Solving reverses that order — we undo addition first, then multiplication. Think of it as undoing PEMDAS from the outside in.