Question

(2x+3y+4)(2x+3y-4)
My answer is :
4x^2+12xy+9y2-20y. ?

Answer 1

when we use foil we get
2x*2x+2x*3y-(2x*4)+3y*2x+3y*3y-(3y*4)+4*2x+4*3y-(4*4)
4x^2+6xy-8x+6xy+9y^2-12y+8x+12y-16
combine like term add/subtract...

Answer 2

final answer 4x^2+12xy+9y^2-16

Answer 3

There's a nifty trick for expanding certain polynomials.
(a+b)(a-b) = a² - b²

Here, let a = 2x + 3y, and b = 4:
(2x + 3y)² - 4² is a fair bit simpler to expand, isn't it?

Answer 4

yep indeed @DDCamp its much easier

Answer 5

But what happen with the 8x?
I'm missing something

Answer 6

Oh I fo be it and just at got

Answer 7

the 8x cancels out

Answer 8

Yes

Answer 9

im telling u that not asking you...lol

Answer 10

Lynn here is my next problem and what I came up with.. Let me know if can help.

Answer 11

Sorry I was answering lol

Answer 12

ok

Answer 13

(5x+2y+3)(5x+2y-3)
This is what I came up with:

25x^2+20xy-15x+4y^2-6y?

Answer 14

Wait wait I gave you my incorrect answer I will give you my results right now

Answer 15

My correct answer is:
25x^2+20xy+4y^2-9

Answer 16

The -15 clear with the positive 15..

Answer 17

InspectorJoe 0
My correct answer is:
25x^2+20xy+4y^2-9

Answer 18

yep ur correct

Answer 19

YES

Answer 20

YEAH

Answer 21

Lol

Answer 22

Oh yes