Garvey's Electronic store is having a storewide sale. For a television set with a regular price of x dollars, a 15 percent discount is equal to $30. Which of the following equations could not be used to determine x?

0.15x=x-30

0.85x=x-30

x-0.15x=x-30

0.15x=30

With the equation:

0.15 x = 30

x = 30 : 0.15 = $200

A regular price of TV is $200.

Which could not be used to determine x (we shall plug in the value 200):

A) 0.15 * 200 = 200 - 30

30 ≠ 170

B) 0.85 * 200 = 200 - 30

170 = 170 (correct)

C) 200 - 0.15 * 200 = 200 - 30

200 - 30 = 200 - 30

170 = 170 (correct)

D) 0.15 * 200 = 30

30 = 30 (correct)

Answer:

A) 0.15 x = x - 30