Question

Factor completely
x 3 +2x 2 -15x


A. 5x (x+1)(x -3)
B. x (x +5)(x +3)
C. -3x (x +5)(x +1)
D. x (x -3)(x +5)

Answer 1

So

x^3 +2x^2 -15x

Let's take out a greatest common factor first, which is x

x(x^2 + 2x - 15)

Now let's factor the trinomials, we need two numbers whose product is -15 and the sum is 2. That would be (5 and -3!)

so


x(x^2 + 2x - 15)
= x(x+3)(x-5) [you switch the signs when you put the factors in the bracket

Answer 2

I'm still confused. Its the answer going to be B? #pottersheep