Question 956929
A=area=21 sq ft; W=width; L=length=W+4ft
{{{LW=A}}} Substitute for L
{{{(W+4ft)(W)=21ft^2}}}
{{{W^2+4W=21ft^2}}} Subtract 24ft^2 from each side.
{{{W^2+4W-21ft^2=0}}}
{{{(W+7)(W-3)=0}}}
W=-7 or W=3 ANSWER 1: The width is 3 feet.
L=W+4ft=3ft+4ft=7FT ANSWER 2: The length is 7 feet.
CHECK:
{{{A=LW}}}
{{{21ft^2=(7ft)(3ft)}}}
{{{21ft^2=21ft^2}}}