Question

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Answer 1

First, take 5 out of the equation:
\[5 \times (x^2- 16y^2)\]
Now the latter part can be factored into something of the form:
\[(x+ay)(x-ay)\]

Answer 2

Where a is the square root of a constant integer.

Answer 3

@Falkqwer If you post what you think the answer is we will check it for you

Answer 4

Exactly.

Answer 5

XD I'm smart lol ^_^