Question 128995
you have to find the length and the width of the rectangle
let denotate L=length and W=width

L=W+4


area = L*W =45 then (W+4)W=45 then W^2+4W-45=0
then {{{W = (-4 +- sqrt( (4)^2-4*1*-45 ))/(2*1) }}}
=  {{{ (-4 +- sqrt(196))/(2*1) }}}
={{{ (-4 +- 14)/2 }}}
={{{ (-2 +- 7) }}}
solutions are  W=-9 and W=5 then W=5

then W=5 and L=9