Question

Question #49a3a

Answer 1

`55a^2+24a-16`

Explanation:

If I understood you correctly you mean
`(7a+a)^2-(-4+3a)^2`
otherwise feel free to correct me.
1. Calculate `7a+a`

`7a+a=8a`

1. Square the brackets using the binomial formula

`(a+b)^2=a^2+2ab+b^2`

`(8a)^2-(3a-4)^2=8^2a^2-(3^2a^2-4*3*2a+4^2)`

1. Simplify

`8^2a^2-(3^2a^2-4*3*2a+4^2)=64a^2-9a^2+24a-16=55a^2+24a-16`

Answer 2

`-2a^2 +7a+4`

Explanation:

In the absence of any formatting, the meaning of the question is not clear. Here is another interpretation which I think is more likely because there is nothing to indicate that the given powers are for the whole expressions.

We have: second expression minus the first expression:

`(7a+a^2) color(blue)(- (-4+3a^2))`

`=7a+a^2 color(blue)(+4-3a^2)" "larr` multiply out the bracket

`= -2a^2 +7a+4" "larr` simplify the like terms.