If fx 713x evaluate f 12 f 12 Preview Solution1 fx 7x 12 y

If f(x) -7-13x, evaluate f (12) f 12) Preview

1. f(x) = 7x -12

y = 7x -12

to find f^-1(x): replace x with y and y woth x and solve

x = 7y -12

7y = (x+12)

y = (x+12)/7

f^-1(x) = ( x+12)/7

f^-1(-12) = ( -12+12)/7 =0

2. f(x) = 3x -6

y = 3x -6

Finf f^-1(x):

x = 3y -6

3y = (x+6)

y = (x+6)/3

f^-1(11.5) = (6+11.5)/3 = 17.5/3 = 5.83

f^-1(y) = 21.5

21.5 = (x+6)/3

x = 58.5

Hence y = 58.5

f^-1{ f(b)} = -8

f(b) = 3b -6

f^-1(3b -6) = ( 3b -6 +6)/3 = b =-8

So, f^-1{ f(b)} = -8 ---> b = -8