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 )

A ) 0.15 x = x - 30

It equals 1373.5 that’s the solution