Chapter 8 - Section 8.4 - Equations Quadratic in Form - Exercise Set - Page 635: 10

{$4,16$}

Since, $u^2-6u+8=0$ Factorize the expression as follows: $(u-4)(u-2)=0$ or, $u=${$2,4$} Replace $u$ with $\sqrt x$, we have $\sqrt x=2$ or, $x=4$ or, $\sqrt x=4 \implies x=4^2$ and $x=16$ Hence, our solution set is $x=${$4,16$}