Question

(2x-7)(2x+7)

Answer 1

This is what I come up with :
4x^2+9x
-9x+49?

Answer 2

4x^2-81+49 final results?

Answer 3

7 * -7 = -49
otherwise correct.
Combine like terms

Answer 4

where did 81 come from?

Answer 5

Sorry correction final answer

4^2+49
?

Answer 6

Because the middle section clear since it comes to zero right

Answer 7

Right the middle clears. Should be
\[4x^2-49\]

Answer 8

because 7 * -7 = -49

Answer 9

Yes b cause a negative x a positive always equal to a negative

Answer 10

right

Answer 11

Thanks a bunch I will attempt the next one in my one and summit here to double check my results

Answer 12

ok

Answer 13

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

Answer 14

The first three terms are right. You may have made a mistake when combining.

\[(2x+3y+4)(2x+3y-4)\]
\[= 2x(2x+3y-4) + 3y(2x+3y-4) + 4(2x+3y-4)\]
\[=4x^2 + 6xy - 8x + 6xy + 9y^2 - 12y + 8x + 12y - 16\]
\[= 4x^2 + 12xy + 9y^2 - 16\]