Question

Find the product of (3x + 7y)(3x − 7y).

9x^2 − 42xy + 49y^2

9x^2 + 42xy + 49y^2

9x^2 − 49y^2

9x^2 + 49y^2

@jim_thompson5910 How would I do this?

Answer 1

Have you heard of the foil method?

Answer 2

No. o.o

Answer 3

lol, well get ready! :)

the foil method, is where you take the first term...in the first set of parenthesis...and multiply it by every term in the second set of parenthesis.

meaning here

(3x + 7y)(3x − 7y).

take 3x.....and multiply it by each term in the second parenthesis....(3x...and -7y)

so

what is

3x times 3x?

and what is

3x times -7y?

Answer 4

Oh, okay. I've done something like that before, just never heard the name of it. I'll try it now :)

Answer 5

yeah, and then do the same thing for the second term in the first parenthesis...then combine...

let me know what you get :)

Answer 6

http://www.sketchtoy.com/35388843 How would I combine this?

Answer 7

You basically have the answer.....but first....what is 3x times 3x?

remember you need to multiply the x's as well

same for the -49y

what is 7y times -7y?

Answer 8

Oh, sorry. I got sidetracked during my movie and forgot to multiply. XD Let me fix that real quick.

Answer 9

haha no problem :)

Answer 10

Wait. I think I did it correctly. o.o What did I do wrong?

Answer 11

Look at it like this...and sorry about the big writing lol

http://www.sketchtoy.com/35389383

Answer 12

Oh! Exponents, right?

Answer 13

exactly!

so what would your final answer be?

Answer 14

The third one, right?

Answer 15

correct! :)

Answer 16

Thanks :)

Answer 17

anytime!