Diketahui f(x)=ax+b. Jika f (1)= -4 dan f(3) 2, nilai f (-2)+f(5)=.......

jawab
f(x)= ax + b

f(1)= - 4
f(3)= 2......(-)
(1- 3)a = - 6
-2a = - 6
a = 3

f(3)= 2
b= 2 - 3a
b = 2-9
b = - 7

f(x)= 3x - 7
f(-2) + f (5) = 3(-2) -7 + 3(5) - 7
= - 6 - 7 + 15 - 7
= - 5