John R. answered 04/10/13
John R: Math, Science, and History Teacher
f(x) = 5x - 3 - 7x + 8 Given
f(x) = -2x + 5 Combine like terms to simplify the expression
y = -2x + 5 Substitute y for f(x)
x = -2y + 5 Switch x and y
x - 5 = -2y Subtract 5 from each side
(x - 5)/(-2) = y Divide each side by -2
y = (5 - x)/2 Distribute the negative to the numerator to simplify the expression
f-1(x) = (5 - x)/2 Replace y with f-1(x)