Question 885186
let x = length of building
    y = width of building

x = 2y + 2

xy = 60

Substituting,

(2y + 2)(y)= 60
2y^2 + 2y = 60
y^2 + y = 30
y^2 + y - 30 = 0
(y + 6)(y - 5)=0
y = -6 | y = 5
Since lengths can only be positive, then y = -6 cannot be a possible answer
So y = 5m

xy=60
x(5)=60
x=12m

length = 12m
width = 5m