1. ## Factoring Assingment

hi, im doing this factoring assignment, and i cant figure out some of the problems , i'd be extremely glad if someone could help me.

(2m+8)^2 - (4m+5)^2 I have no idea how to start with this one

x^2 - 21x -72

(x-2)^2 -16 Is this one a difference of squares? and how do
i resolve it?

25x^2 +30xy + 9y^2 is this a tough polynomial? because i have no
idea how to resolve it, i got confused, or should i
resolve it using common factoring, only i've tried that and didnt work...

2. Originally Posted by lausalas
hi, im doing this factoring assignment, and i cant figure out some of the problems , i'd be extremely glad if someone could help me.

(2m+8)^2 - (4m+5)^2 I have no idea how to start with this one

(2m+8)*(2m+8)-((4m+5)*(4m+5))
foil these out and then simplify.

x^2 - 21x -72
look for terms that multiply to -72 but add to -21
(x- )(x+ )

(x-2)^2 -16 Is this one a difference of squares? and how do
i resolve it?
if you had (x^2-9) this would also be a difference of squares and it would factor to (x+3)(x-3)=0

25x^2 +30xy + 9y^2 is this a tough polynomial? because i have no
idea how to resolve it, i got confused, or should i
resolve it using common factoring, only i've tried that and didnt work...

3. thanks you

but im still not sure how to do this one

(x-2)^2 -16, so then, is not a diference of squres, then what is it?

4. Originally Posted by lausalas
thanks you

but im still not sure how to do this one

(x-2)^2 -16, so then, is not a diference of squres, then what is it?
It is a difference of squares. $[x-2]^2-4^2$. Factor it like normal.

5. Originally Posted by lausalas
thanks you

but im still not sure how to do this one

(x-2)^2 -16, so then, is not a diference of squres, then what is it?
It is a difference of squares. I was just giving you an example to go by.
If your problem was (x^2-16) would you know how to do it?
For example, if the problem was (x^2-49). It would factor to (x-7)(x+7)=0
If you foil those two you get back to (x^2-49), right?
For your problem think of the (x-2)^2 as being simply x^2. Everywhere you would put x just put (x-2). Okay?