Question 949487
W=width; L=length=2W+11 ft; A=area=L*W=63 sq ft
A=L*W Substitute for L
{{{63 sq ft=(2W+11)(W)}}}
{{{63 sq ft=2W^2+11W}}} Subtract 63 sq ft from each side
{{{0=2W^2+11W-63 sq ft}}}*[invoke quadratic "W", 2, 11, -63 ]
W=3.5 ft ANSWER the width is 3.5 feet.
L=2W+11 feet=2(3.5 feet)+11 ft=18 feet ANSWER The length is 18 feet.
CHECK
A=L*W
63 sq ft=18 ft*3.5 ft
63 sq ft=63 sq ft