The area of a rectangular floor is described by the equation w(w-9)=252 where w is the width of the floor in meters. What is the width o the floor?

1 Answer
Jun 3, 2016

Width (w) = 21

Explanation:

Given:
w(w-9)=252

Multiply everything inside the brackets by w

=>w^2-9w=252

Subtract 252 from both sides

w^2-9w-252=0

Factors of 252 that have a difference of 9 are 12 and 21
We need -9 so the larger if the two is negative.

(w-21)(w+12) =w^2+12w-21w-252color(red)(" Works")

So
w-21=0" " =>" " w=+21
w+12=0" "=>" "w=-12 color(red)(larr" negative value not logical")

Width (w) = 21