I hope someone can help me because i'm stumped

This problem is in the maths applied level 3 & 4.

The concrete slab in the shape of a rectangle shown on the right has an area of 63m^2. Form a Quadratic Equation and solve for "x" and then determine thewidthandlengthof the rectangle in order for it to be paved.

(you can't use trial and error or guessing)

Hope Someone can help me out

Cheers OLLiE