Question

F(x) = 5(x+4) − 6, solve for the inverse function when x = 19

Answer 1

-1

Explanation:

First find the inverse function. Rewrite the given function as

y = 5(x + 4) - 6 = 5x + 20 - 6 = 5x + 14

Second, interchange x and y:

x = 5y + 14

Third, solve this result for y:

5y = 14 - x, or y = (1/5)(14 - x)

This last result is the inverse function of the given f(x).

The value of this inverse at x = 19 is (1/5)(14 - 19) = (1/5)(-5) = -1