So WX is 7y +4 and XY is 21, and when you add those lines you get the whole thing, which is 12y so write that like an equation
12y = 7y+4+21
12y = 7y+25
5y = 25
y = 5
Answer:
A and B
Step-by-step explanation:
Because the surface area is 
BA is the base, so
also works.
A= 2 WL+ 2 LH+ 2 HW.
W= width
L= length
H= height