Answer
4 ft and 9 ft
Work Step by Step
Let the width, $w$, of the plywood be $x$. Then the length, $l$, will be $x+5$.
Now, the area A is given by
$$A=lw\Longrightarrow 36= x(x+5).$$
Expanding gives:
$36=x^2+5x$
$x^2+5x-36=0$
By factorization, we have
$$(x+9)(x-4)=0\Longrightarrow x=4 \ or \ x = -9.$$
Then, $w=x=4 \ ft$ and $l=x+5=4+5=9 \ ft.$
