I think the length is 21 in because...
the width (W) is x-9
X(x-9)=252
X^2 -9x-252=0
(X-21)=0 and (x+12)=0
x=21 or x=-12
the only one that works is 21 and I checked the answer so I'm pretty sure it's 21
For this number, I think the scale is 5m for every 4 cm. Therefore, the 4 cm drawn in the plan is really equal to 5m and the 5 cm is equal to 6.25m. The actual area of the bedroom is determined by multiplying the real dimensions. That is,
actual area = (5m)(6.25m) = 31.25 m²
Thus, the answer is 31.25 m².
After factoring you will get (x+5)(3x-1)