Question 555567
Let width be "x"

So length = x+7

Hence area = x*(x+7) which is equal to 450

> x^2 + 7x = 450

>  x^2 + 7x -450=0

> x^2 + 25x - 18x -450=0 

> x(x+25) -18(x+25)=0
> (x-18) (x+25)

> x = 18 or -25

Ans = length of the shorter side 18m