Question

Use the remainder theorem to find the value of k when x3+2x2+kx+3 is divided by x-3 then the remainder is 21

Answer 1

Hello friend

Let p(x)=x³+2x²+kx+3

Remainder when divided by x-3 is 21

x-3=0

x=-3

p(-3)=21

p(-3)=-3³+2(-3)²+k(-3)+3

21= -27+18-3k+3

21= -27+21-3k

21+27-21= -3k

27/-3=k

k= -9

Hope it helps ^_^