Question

if x^3 -2ax+15 is divisible by x+5, find a​

Answer 1

Answer:

let p(x) x-5=0,

p(x) x= -5

By the remainder theorem, we know that when p(x) is divided by(x+5) then the remainder is p(-5)

p(-5) =x^3-2ax+15

=(-5) ^3-2 ×a×-5+15

= - 125+10a+15

=-110+10a

=10a=110

=a=110/10

a=11