Question

x^2 y^2 -64 factorise

Answer 1

${x}^{2} {y}^{2} - 64 \\ = {(xy)}^{2} - {(8)}^{2} \\ = (xy + 8)(xy - 8)$

Identity applied:

${a}^{2} - {b}^{2} = (a + b)(a - b)$