Question

The function f is defined by f(x)=3x+k, where k is a constant. Find k, if the graph of f passes through the point (−1,8).

Answer 1

k = 11

Explanation:

f(x)=3x+k,

We know the input is -1 so replace x with -1 and the output is 8 so replace f(x) with 9

8 = 3(-1) +k

8 = -3+k

Add 3 to each side

8+3 = -3+3+k

11= k