Chapter P - Prerequisites: Fundamental Concepts of Algebra - Exercise Set P.3 - Page 51: 137

3

$ (5 + \sqrt x) ( 5 - \sqrt x) = 22$ $(a+b)(a-b) = a^{2} -b^{2}$ So, $5^{2} - (\sqrt x)^{2} = 22$ $25 - (\sqrt x)^{2} = 22$ $25 - 22 =(\sqrt x)^{2}$ $3 =(\sqrt x)^{2}$ $(\sqrt x)^{2} = 3$ $\sqrt x = \sqrt 3$ $x = 3$