Question

Which of the following are roots of the polynomial function?
Check all that apply.
F(x) = x3 + 3x2 - 9x+ 5
O A. -5
OB. 1 + 3
O C. 3+2
O D. 1-3
O E. 1
O F. 3 - 2

Answer 1

Answer:

1 and -5

Step-by-step explanation:

$~~~~~x^3+3x^2-9x+5=0\\\\\implies x^3-x^2+4x^2-4x-5x+5=0\\\\\implies x^2(x-1)+4x(x-1)-5(x-1)=0\\\\\implies (x-1)(x^2 +4x -5) = 0\\\\\implies (x-1)(x^2+5x -x -5) = 0\\\\\implies (x-1)[x(x+5) -(x+5)] =0\\\\\implies (x-1)(x-1)(x+5)= 0\\\\\implies (x-1)^2(x+5) = 0\\\\\implies x = 1,~~ x = -5$