Question

If X square + 1 by x square is equal to 7 find values of 3 x square minus 3 by x square

Answer 1

Given

${x}^{2} + \frac{ 1 }{ {x}^{2} } = 7$

Solution

${(x + \frac{1}{x}) }^{2} \\ = {x}^{2} + \frac{1}{ {x}^{2} } + 2.x. \frac{1}{x} \\ = 7 + 2 \\ = 9$

Therefore,

$(x + \frac{1}{x} ) = \sqrt{9} = 3$

Now,