Question 941480
 surface area of rectangular floor =  126 sq fr
 let  x be the width
length  = 2x+4
  area  =  length * width
 126 =(2x+4)*x
{{{ 126 = 2x^2+4x}}}
 move 126 to  the right
 {{{ 0 =2x^2+4x-126}}}
 *[invoke quadratic "x", 2, 4, -126 ]

 x= 7 or -9
but x represents width. it cannot be negative
hence x= 7 
 width  (x) = 7 feet