Question

Which of the following statements describes a correct method for solving the equation below?
20 + 2w = 50

A) Add 20 to both sides of the equation, and then divide both sides by 2.

B) Subtract 20 from both sides of the equation, and then divide both sides by 2.

C) Divide both sides of the equation by 2, and then add 20 to both sides.

D) Divide both sides of the equation by 2, and then subtract 20 from both sides.

Answer 1

30 + 2w = 2 • (w - 15)

Equation at the end of step 1 :
Step 2 :
Equations which are never true :
Solve : 2 = 0

This equation has no solution.
A a non-zero constant never equals zero.

Solving a Single Variable Equation
Solve : w-15 = 0

Add 15 to both sides of the equation :
w = 15

Answer 2

You are trying to solve for "w", to do so you:

20 + 2w = 50     Subtract 20 on both sides  

2w = 30  Divide 2 on both sides to get "w" by itself

w = 15

Your answer is B