Answer:
A. add 81; 
Step-by-step explanation:
The perfect square formula

Rewrite expression
as follows:

So, to form a perfect square,
is missed.
When we add
we will get

Step-by-step explanation:
EF = 4x - 15
FG = 3x - 7
EG = EF + FG = 20
so,
4x - 15 + 3x - 7 = 20
7x - 22 = 20
7x = 42
x = 6
EF = 4×6 - 15 = 9
FG = 3×6 - 7 = 11
m<E=45.5 m<F=45.5
this is question 8 can't see question 9
1) calculate the volume of the tri prism 2) find area of the base face 3) find the height 4) multiply area of the triangle base time height 5) answer will be in cubic units