Question

Find the dimensions of a rectangle whose width is 10 meters less than its length, and whose area is 416 square meters.

Answer 1

I would say that if you were trying to solve this problem maybe you should ask your teacher for the answer and then hold him captive

Answer 2

Check the picture below.

`Lw=416\implies L(L-10)=416\implies L^2-10L=416 \\\\\\ L^2-10L-416=0\implies (L-26)(L+16)=0\implies L= \begin{cases} ~~ ~26 ~~ \checkmark\\ -16 ~~ \bigotimes \end{cases} \\\\\\ ~\hspace{22.5em}\stackrel{ 26~~ - ~~10 }{\boxed{w=16}}`

let's notice that -16 is valid, however it doesn't apply in this case since the length can't be negative.