Question

the expression f(x)=x³+ax²+bx+c leaves the same remainder,R, when it is divided by x+2 and when it is divided by x-2. evalute b. please help i need this as soon as possible (today please)

Answer 1

Answer:

b = -4

Step-by-step explanation:

f(2) = R  and f(-2) = R

Therefore f(2) = f(-2):-

(2)^3 + a(2)^2 + 2b + c =  (-2)^3 +a(-2)^2 - 2b + c

8 + 4a + 2b+ c  = -8 + 4a - 2b + c

The 4a and  c  cancel out. Then:-

8 + 2b = -8 - 2b

4b = -16

b = -4    answer