Solution:
Note that:
Divide the length of the court by 2x to find the width of the court.
[tex]\\ \rm\hookrightarrow 6x^2+20x=2x[/tex]
[tex]\\ \rm\hookrightarrow 6x^2=-18x[/tex]
[tex]\\ \rm\hookrightarrow x^2=-3x[/tex]
[tex]\\ \rm\hookrightarrow x=-3[/tex]