how do you factor
-8x^2 + 40xy + 112y^2 ?
I know to take the -8 out, but after that I'm stuck..
-8x^2 + 40xy + 112y^2 ?
I know to take the -8 out, but after that I'm stuck..
-
Okiedokie, let's work this step by step, mmhm?
So yes, let's remove that nasty -8.
so we have -8 (x^2 - 5xy - 14y^2), yes? Remember to flip the sign since we took out a negative 8.
now, since we have a " - 14y^2" at the end, we know that once we make this two separate binomials, one will have a "+" and the other will have a "-", yes?
we'll have (x +/- y) (x -/+ y), right? One will be + and the other will be -. They'll both have an x and a y so that when we FOIL it out, we have x^2, xy, and y^2 for terms, yes?
Now, we need to see what factors of -14 can add together to get -5
after some guessing and checking, we see that -7 and +2 work perfectly for this!
So, we'll plug those in and get...
-8 (x-7y) (x+2y)
i hope that made sense, i know that wasn't the greatest explanation ever..
So yes, let's remove that nasty -8.
so we have -8 (x^2 - 5xy - 14y^2), yes? Remember to flip the sign since we took out a negative 8.
now, since we have a " - 14y^2" at the end, we know that once we make this two separate binomials, one will have a "+" and the other will have a "-", yes?
we'll have (x +/- y) (x -/+ y), right? One will be + and the other will be -. They'll both have an x and a y so that when we FOIL it out, we have x^2, xy, and y^2 for terms, yes?
Now, we need to see what factors of -14 can add together to get -5
after some guessing and checking, we see that -7 and +2 work perfectly for this!
So, we'll plug those in and get...
-8 (x-7y) (x+2y)
i hope that made sense, i know that wasn't the greatest explanation ever..
-
-8(x^2 - 5xy - 14y^2)
- 8(x - 7y)(x + 2y)
- 8(x - 7y)(x + 2y)