Question

If
$x + {x}^{ - 1} = 11$
evaluate
${x}^{2} + {x}^{ - 2}$
​

Answer 1

Answer:

119

Step-by-step explanation:

$x + {x}^{ - 1 } = 11$

squaring both sides we get,

${x}^{2} + {x}^{ - 2} + 2 \times {x }^{2} \times {x}^{ - 2} = 121$

or,

${x}^{2} + {x}^{ - 2} + 2 = 121$

or,

${x}^{2} + {x}^{ - 2} = 119$