When the polynomial P(x) = 3x^3 + kx^2 + 45x + 25 is divided by x + 5, the remainder is 0. Which of the following is also a factor of P(x)
A.)3x-5
B.) x-1
C.) 3x+5
D.) 3x+1

Question

When the polynomial P(x) = 3x^3 + kx^2 + 45x + 25 is divided by x + 5, the remainder is 0. Which of the following is also a factor of P(x) 
A.)3x-5
B.) x-1
C.) 3x+5
D.) 3x+1

anonymous · Answer

Is it C?:(

anonymous · Answer

@UnkleRhaukus :(

anonymous · Answer

@123AB456C can  u help me :/

whpalmer4 · Answer

what do you get when you do that division?

freckles · Answer

First use remainder theorem to find k
you are given P(-5)=0 <--use this to find k
this is first step

whpalmer4 · Answer

didn't see that $k$ lurking in there, @freckles has the right approach.

mathmale · Answer

If the remainder is zero, that indicates that -5 is a root.  That -5 comes from (x+5), which in turn is a factor of the polynomial in question.

Kindly use synthetic division to divide the given polynomial by (x+5).  Use -5 as your divisor there.  The result must give you a remainder of zero; the 3 non-zero terms are the coefficients of a quadratic factor of the given polynomial.  What next?

mathmale · Answer

Please show your work in performing this synthetic division, so that others may give you meaningful feedback.