Question

Let f(x) = 2x − 6. solve f−1(x) when x = 2. select one: a. −5 b. 4 c. −2 d. 7

Answer 1

F(x) = 2x - 6

y = 2x - 6
2x - 6 = y  |add 6 to both sides
2x = y + 6    |divide both sides by 2
x = 1/2y + 3

f^{-1}(x) = 1/2x + 3

f^{-1}(2) = 1/2 · 2 + 3 = 1 + 3 = 4

Answer: b. 4