Step-by-step explanation:
x = number
3x - 15 = (x - 12)×-4 or (12-x)×-4
3x - 15 = -4x + 48 or -48 + 4x
7x = 63, x = 9 or
33 = x
48 inches to 30 inches is a decrease.
percent decrease = change/original value x 100%
= (48 - 30)/48 x 100%
= 18/48 x 100%
= 37.5% decrease