Question 614333
the width is just w and the length we can describe it as 4w-6 and the area is w*l=40 and if we multiply them we get the equation {{{4w^2-6w=40}}}*[invoke quadratic "x", 4, -6, -40 ] 
and we take the positive answer of 4 as the width and the lenth is 4(4)-6=10