algebra graphing

Question

5x^2-9x-18 and the other one is x^2+6x-12=-5

Answer 1

Hi Chase!

5x^2-9x-18

If you factor, the question you want to ask yourself is what are the factors of 5 and what are the factors of -18.

We know the factors of 5 to be: (-)1,(-)5.

We know the factors of -18 to be: (-)1,(-)2,(-)3,(-)6,(-)9,(-)18.

After we put these factors into our polynomial, we get (x-3)(5x+6).

[x=3,-6/5]

We could have also used the quadratic formula.

We could have also used the payback method.

x^2+6x-12=-5

The first thing we want to do is set this polynomial equal to 0 by adding 5 to both sides. We get x^2+6x-7=0

Now we have to find the factors of 7 which we know to be (-)1 and (-)7.

What two numbers multiply to get you -7 and add to get you 6? 7 and -1.

We are left with (x+7)(x-1)

[x=-7,1]