Question

answer this question

Answer 1

${(x - \frac{1}{x}) }^{2} = {x}^{2} + \frac{1}{ {x}^{2} } - 2 \times x \times \frac{1}{x} \\ {7}^{2} = {x}^{2} + \frac{1}{ {x}^{2} } - 2 \\ 49 + 2 = {x}^{2} + \frac{1}{ {x}^{2} } \\ 51 = {x}^{2} + \frac{1}{ {x}^{2} } \\ {( {x}^{2} + \frac{1}{ {x}^{2} }) }^{2} = {x}^{4} + \frac{1}{ {x}^{4} } + 2 \times {x}^{2} \times \frac{1}{ {x}^{2} } \\ {51}^{2} = {x}^{4} + \frac{1}{ {x}^{4} } + 2 \\ 2601 - 2 = {x}^{4} + \frac{1}{ {x}^{4} } \\ 2599 = {x}^{4} + \frac{1}{ {x}^{4} }$
therefore value of x4 plus 1 upon x4 is 2599