Square a and rectangle b have the same width. the length of rectangle b is 4 cm greater than its width. the area of rectangle b is 20 cm greater than the area of square a

set up an equation and solve it to find the area of square a.

-! : d

Noting that square A is a square, this is what we have:
A = B
A^2 = B x (B + 4) + 20

I can try subbing in A to B
since A = B:

A^2 = A x (A + 4) + 20
20 = A^2 - (A x (A + 4))
20 = A^2 - (A^2 + 4A)
20 = 4A
A = 5

By the way, A is width of square A and B is the width of rectangle B in my solution,

Ithink it's b sorry if i'm wrong