suatu fungsi f(x) = mx+ n. jika f (4) = -5 dan f(-3) = 9, maka f(2) adalah

f(x) = mx + n

f(4) = -5
4m + n  =  -5 .... (1)

f(-3) = 9
-3m + n = 9 ... (2)


4m +n = -5
-3m + n = 9
-------------------- -
7m = -14
m = -2

substitusi nilai

4m + n = -5
4(-2) + n = -5
n = -5 + 8
n = 3

jadi jika disusun fungsi jadinya
f(x) = -2x + 3
f(2) = -2 (2) + 3
f(2) = -4 + 3
f(2) = -1