Question

If f(x)=8x+6, what is f(-1)

Answer 1

If I remember correctly this is how you solve it.

f(x)=8x+6
f(-1)=8(-1)+6
f(-1)=-8+6
f(-1)= -2

Answer 2

F(x) = 8x + 6

To find f(-1), substitute x = -1 :

f(-1) = 8(-1) + 6 = -8 + 6 = -2

Answer:  f(-1) = -2