Answer:
a. 20
b. 25
Step-by-step explanation:
Let find the side lengths of the rectangle,
We can complete the square.






or


or

This means the perimeter of is
2 times -7 equal 14
2 times 3 equal 6
14+6=20.
The side lengths of the square is equal so each side length will measure 5.

Step-by-step explanation:
a^4-6a^2-7-8x-x^2
a^4-6a^2-8x-x^2-7
-5a^2-9x^3-7
The answer would be
(c+d)-3