Question

Question #5a96c

Answer 1

`(5a-8b)(5a-8b) = (5a-8b)^2`

Explanation:

`25a^2-80ab+64b^2`

This is actually much easier than is appears at first glance.

Note that both `25 and 64` are perfect squares.

In `(2a+3b)^2 = 4a^2 +12ab +9b^2`
`color(white)(xxxxxxxxxxxxxxx)uarr`
The middle term is double the product of 2 and 3

Check if that is the case here: `(5xx8) xx 2 = 80" "` BINGO!

`(5a-8b)(5a-8b) = (5a-8b)^2`

If you did not spot that, you would need to read it as:

"Find factors of 25 and 64 which ADD to 80"