Dikietahui fungsi f(x) = ax + b. Jika f(2) = -2 dan f(3) = 13,

Maaf tulisannya gaje

F(x) = ax + b

f(2) = a(2) + b = 2a + b
f(3) = a(3) + b = 3a + b

eliminasi
2a + b = -2
3a + b = 13
_________-
-a = -15
a = 15

substitusi
2a + b = -2
2(15) + b = -2
30 + b = -2
b = -2 – 30
b = -32

rumus fungsi
f(x) = 15x – 32

f(4) = 15(4) – 32 = 60 – 32 = 28