Question

Find the product using a suitable identity (i) (3xy - 5)2
(ii) (abc + 9) (abc - 9)​

Answer 1

Step-by-step explanation:

$(3xy - 5)² \\ = (3xy) {}^{2} -2 \times 3xy \times 5 + ( 5)² \\ = 9 {x}^{2} {y}^{2} - 30xy + 25$

$(ii) (abc + 9) (abc - 9) \\ = (abc ) {}^{2} -( 9) {}^{2} \\ = a {}^{2} b {}^{2} c {}^{2} - 81$