1. Isolate the variable. Subtract 7 from both sides of the equation. (4x+7-7 = 15-7)
2. ( 4x = 8) This is what you should come up with after subtraction.
3. Divide (4x=8) by 4 to isolate x.
4. After dividing both sides by 4, (x=2) should be the answer.