Question 189626
Let x=width of the rectangle
2x+2=length of the rectangle

If Area=length x width
{{{x*(2x+2)=60}}}
{{{2x^2+2x=60}}}
{{{2x^2+2x-60=0}}}
{{{(2x+12)(x-5)=0}}}
2x+12=0  and x-5=0
2x+12-12=0-12
2x=-12
x=-6, but the width cannot be negative

x-5=0
x-5+5=0+5
x=5, width is 5km

2(5)+2=12km

The length of the rectangle is 12km