Question

If a-1/a=8 and a≠8 find: a²-1/a²

Answer 1

Answer:

let a=x

$x - \frac{1}{x} = 8$

take square on both side:

${x}^{2} - 2 + 1 \div {x}^{2} = 64$

${x}^{2} - 1 \div {x}^{2} = 64 + 2$

${x}^{2} + 1 \div {x}^{2} = 66$