Question 750749
A square yard has a 6-foot wide sidewalk around a square lawn. the sides of the yard, including the sidewalk, have length y. evaluate for y=70, the polynomial that gives the area of the sidewalk. 

the area of the square including the sidewalk is y^2
the area of the sidewalk is y^2 - (y-12)^2
y^2 - (y^2 -24y +144)
y^2 -y^2 +24y -144

we are left with

24y - 144 = 24*70 -144 = 1536