Question

factorize x square - y square by 9​

Answer 1

$x {}^{2} - \frac{ {y}^{2} }{9} \\ \\ = (x) {}^{2} - ( \frac{y}{3} ) {}^{2} \\ \\ = (x + \frac{y}{3} )(x - \frac{y}{3} )$