Question 861680
{{{A=12}}}
{{{lw=12}}}
Because the width is 4 ft shorter,
{{{l(l-4)=12}}}
Distribute the l
{{{l^2-4l=12}}}
Subtract 12 from both sides
{{{l^2-4l-12=0}}}
Use the quadratic formula
{{{l = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
{{{l = (4 +- sqrt( -4^2-4*1*-12 ))/(2*1) }}}
{{{l = (4 +- sqrt(16+48))/(2) }}}
{{{l=(4+-sqrt(64))/2}}}
{{{l=(4+8)/2}}}OR{{{l=(4-8)/2}}}
{{{l=12/2}}}OR{{{l=-4/2}}}
{{{l=6}}}OR{{{l=-2}}}
Because the length can't be negative, l=6. Because the width is 4 less, it's 2.
<h4>The length is 6 feet</h4>