Question

6. on dividing x³+ax²+19x+20 by (x+3), if the remainder is 'a' , then find the value of 'a'.​

Answer 1

Answer:

Let f(x)=x^3+ax^2+19x+20

divisor=x+3

by factors theorem x+3=0=>x=-3

given f(-3)=a

=>(-3)^3+a(-3)^2+19(-3)+20=a

=>-27+a(9)-57+20=a

=>9a-64=a

=>9a-a=64

=>8a=64

=>a=64/8

=>a=8