[tex]h-height\\h+2-width\\35 ft^2-Area\\\\Area=h(h+2)\\\\h(h+2)=35\\h^2+2h-35=0\\\\a=1;\ b=2;\ c=-35\\\\\Delta=b^2-4ac;\ if\ \Delta > 0\ then\ h_1=\frac{-b-\sqrt\Delta}{2a}\ and\ h_2=\frac{-b+\sqrt\Delta}{2a}\\\\\Delta=2^2-4\cdot1\cdot(-35)=4+140=144;\ \sqrt\Delta=\sqrt{144}=12\\\\h_1=\frac{-2-12}{2\cdot1}=\frac{-14}{2}=-7 < 0;\ h_2=\frac{-2+12}{2\cdot1}=\frac{10}{2}=5\\\\Answer:Height\ is\ 5\ ft.[/tex]