Incorrect. The grass patch has length $\displaystyle{36}-{2}{x}\usepackage{cmbright}\Huge\$ feet and width $\displaystyle{24}-{2}{x}\usepackage{cmbright}\Huge\$ feet. Therefore, the area of the grass is $\displaystyle{\left({36}-{2}{x}\right)}{\left({24}-{2}{x}\right)}={540}\usepackage{cmbright}\Huge\$ . Multiply out, rewrite in standard form, divide by 4, and use the Quadratic Formula. The larger solution is impossibly wide, and the smaller solution is the correct value.