Diketahui fungsi f(x)=ax+b. Jika f(2)=-2 dan f(3)=13,tentukan nilai f(4)

F(x)=ax+b.
f(2)= 2a + b = -2
f(3)= 3a + b = 13
============== –
-a = -15
a = 15
3×15 + b = 13
b = 13-45 = -32

f(x) = 15x – 32
tentukan nilai
f(4) = 15(4) -32 = 28