Chapter 8 - Section 8.4 - Equations Quadratic in Form - Exercise Set - Page 635: 12

{$36$}

Since, $2u^2-7u-30=0$ Factorize the expression as follows: $(2u+5)(u-6)=0$ or, $u=${$\dfrac{-5}{2},6$} Replace $u$ with $\sqrt x$, we have $\sqrt x=\dfrac{-5}{2}$ which has no solution and $\sqrt x=6 \implies x=6^2$ or, $x=36$ Hence, our solution set is $x=${$36$}