[tex] {\qquad\quad\qquad\huge\underline{{\sf Answer}}} [/tex]
Here we go ~
[tex]\qquad \sf \dashrightarrow \: {x}^{2} + \cfrac{1}{ {x}^{2} } = 34[/tex]
[ add 2 on both sides ]
[tex]\qquad \sf \dashrightarrow \: {x}^{2} + \cfrac{1}{ {x}^{2} } + 2 = 34 + 2[/tex]
[ form identity : a² + b² + 2ab ]
[tex]\qquad \sf \dashrightarrow \: {(x)}^{2} + { \bigg(\cfrac{1}{ {x}^{} } \bigg) }^{2} + 2 \sdot(x) \sdot \bigg(\cfrac{1}{x} \bigg) = 36[/tex]
[ a² + b² + 2ab = (a + b)² ]
[tex]\qquad \sf \dashrightarrow \: {\bigg (x + \cfrac{1}{x} \bigg) }^{2} = 36[/tex]
[tex]\qquad \sf \dashrightarrow \: {\bigg (x + \cfrac{1}{x} \bigg) }^{} = \sqrt{ 36}[/tex]
[tex]\qquad \sf \dashrightarrow \: x + \cfrac{1}{x} = \pm 6[/tex]
so, the value of required expression is 6
[usually positive value is considered, but if asked the value can be either positive or negative]
