we know that
[volume of a box]=L*W*H
volume=48 ft³
H=2 ft
L=W+2
W=?
then
48=(W+2)*W*2----------> 48=2W²+4W---------> 2W²+4W-48=0
using a graph tool------------> to resolve the quadratic equation
see the attached figure
the solution is
W=4 ft
L=W+2--------> L=4+2--------L=6 ft
the answer is
W=4 ft
