Question

Jika f(x) = mx + n dan f(-2) = -8, f(2) = 4,maka f(7) adalah..

Answer 1

- 2m + n = - 8
  2m + n = 4
 ___________ -
 - 4m = - 12
    m = 3
     n = - 2
f(x) = 3x - 2
f(7) = 3(7) - 2 = 19

Answer 2

F(x) = mx+n
f(-2) = -8
-2m+n = -8 ---> n=2m-8
f(2) = 4
2m+n = 4
2m+2m-8 = 4
4m = 4+8
4m = 12
m = 3
n = 2m-8
  = 2(3)-8
  = 6-8
  = -2

f(x) = 3x-2
f(7) = 3(7)-2
     = 21-2
     = 19