The correct answer maybe
Actually I don't understand ur question
Answer:

Step-by-step explanation:
we know that
To find out the area of the sidewalk, multiply the length by the width of the sidewalk
The width of the sidewalk is equal to

or

The area is equal to

Answer:
third one should be about f
Answer:
Here's what I get
Step-by-step explanation:
a. Write an equation
(8x + 12y)² + (6x + 9y)²= (10x + 15y)²
b. Transform the equation
(i) Remove parentheses
64x² +192xy + 144y² + 36x² + 108xy + 81 y² = 100x² +300xy + 225y²
(ii) Combine like terms.
100 x² + 300xy + 225y² = 100x² +300xy + 225y²
The two sides are the same.
The equation is an identity.