Chapter 8 - Section 8.4 - Equations Quadratic in Form - Exercise Set - Page 635: 1

{$\pm 1, \pm 2$}

Since, $u^2-5u+4=0$ Factorize the expression as follows: $(u-4)(u-1)=0$ or, $u=${$1,4$} Replace $u$ with $x^2$, we have $x^2=1$ and $x^2=4$ This implies that $x=\pm 1, \pm 2$ Hence, our solution set is $x=${$\pm 1, \pm 2$}