Answer:

Step-by-step explanation:
is essentially
(you are squaring
, so multiplying it by itself), so to simplify, you would need to distribute.
A good way to go about this is using the F.O.I.L. method, multiplying the First numbers in the parentheses, then the Outers, then Inners, and finally, Lasts.
>>
>>
>> 
(
)
After doing so, you would end up with
, and after combining like terms,
.
To write the expression in standard form, though, just order the terms from highest to lowest power!
I believe the answer will be 23in
X=7.
9x-7y=63
9x-7 x 0=63
9x - 0=63
9x=63
X=7.
Y=-9
9 x 0 -7y=63