Question

if x = 4 - root 15 then find x to the power 2 - 1 by x to the power 2​

Answer 1

Step-by-step explanation:

$x = 4- \sqrt{15}$

${x}^{2} = (4 - \sqrt{15} )^{2}$

${x}^{2} = 16 + 15 - 8 \sqrt{15}$

${x}^{2} = 31 - 8 \sqrt{15}$

$\frac{1}{ {x}^{2} } = \frac{1}{31 - 8 \sqrt{15} }$

$= \frac{1}{31 - 8 \sqrt{15} } \times \frac{31 + 8 \sqrt{15} }{31 + 8 \sqrt{15} }$

$\frac{31 + 8 \sqrt{15} }{961 - 960}$

$\frac{1}{ {x}^{2} } = 31 + 8 \sqrt{15}$

${x}^{2} - \frac{ 1 }{ {x}^{2} } = 31 - 8 \sqrt{15} - (31 + 8 \sqrt{15} )$

$31 - 8 \sqrt{15} - 31 - 8 \sqrt{15}$

${x}^{2} - \frac{1}{ {x}^{2} } = 16 \sqrt{15}$

THIS IS UR ANSWER AND PLS MAKE A CORRECT THE FINAL ANSWER IS -16 ROOT 15

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