Respuesta :

Answer:

k = 11

Step-by-step 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