diketahui rumus fungsi f(x) = ax + b dika f(6) =13 dan f(-2) = -11 maka f(7) adalah

f(x) = ax + b
f(6) = a(6) + b = 13
f(-2) = a(-2) + b = -11

lalu eliminasi
6a + b = 13
-2a + b = -11
__________-
8a = 24
a = 3

cari b nya dulu:
6(3) + b = 13
18 + b = 13
b = 13-18
b = -5

f(7) = 3(7) - 5
21 - 5 = 16