Question 537689
x, the width empty around the rug


{{{(20-2x)(13-2x)=198}}}

simplifies to 
{{{2x^2-33x+31=0}}}


If use general quadratic equation solution formula

{{{x=(33-sqrt(33^2-4*2*31))/4}}}

{{{x=(33-29)/4}}}


{{{highlight(x=1)}}}