which of the following quartic functions has x=-2 & x=-3 as its only 2 real zeroes?
PLEASE HELP ! IVE TRIED & TRIED

1. x^4-5x^3+7x^2-5x+6
2. x^4+5x^3+7x^2+5x+6
3. x^4+5x^3+7x^2-5x-6
4. x^4-5x^3+7x^2+5x-6

Question

which of the following quartic functions has x=-2 & x=-3 as its only 2 real zeroes?
PLEASE HELP ! IVE TRIED & TRIED

1. x^4-5x^3+7x^2-5x+6
2. x^4+5x^3+7x^2+5x+6
3. x^4+5x^3+7x^2-5x-6
4. x^4-5x^3+7x^2+5x-6

anonymous · Answer

@SolomonZelman

anonymous · Answer

@Lolovitz 
I did what you said & none of them came out right !

anonymous · Answer

so for x=-2  those functions are equal to 
1. 16+40+28+10+6 != 0
2. 16-40+28-10+6=0
3. 16-40+28+10-6!=0
4.16+40+28-10-6!=0
So the only one valid is second
So now let's see if number two is valid for x=-2 if it is valid for x=-3
81-135+63-15+6 =0 So those numbers are zero's for f(x) in number two