Question

product of (5x+3)(5x-3)

Answer 1

What is X?

Answer 2

It is any number, basically nothing.

Answer 3

I know what the definition is, but usually they give it during questions.

Answer 4

Yeah, but I almost never get that, so I just pretend it is nothing.

Answer 5

Multiplication by conjugate
\[(a + b)(a - b) = a^2 - b^2\]
Example
\[(2+7x)(2-7x) = 2^2 - (7x)^2 = 4 - 49x\]

Answer 6

Correction \[4 - 49x^2\]

Answer 7

\[5x*5x= 25x ^{2}\]
\[5x*3= 15x\]
\[-3*5x= 15x\]
\[-3*3= -9\]
\[25x ^{2}-15x+15x-9\]
\[=25x ^{2}-9\]