Question

Given f(x) = x³-4x²+ax+b is divisible by (x²-3x+2) . the value of a-b = ??????

Answer 1

X^2 - 3x + 2 = (x-2)(x-1_
x= 2 atau x =1 

f(1) = (1) - 4 +a+b = 0 
⇔a+b=3
f(2) = 8-16+2a+b=0
⇔2a+b=8

a+b=3
2a+b=8 -
-a = -5
a=5

a+b = 3
b=3-5= -2

a-b= 5+2=7