Question

factorise 27x2 + y2 + 2? - 9xyz using identity.​

Answer 1

$27 {x}^{3} \times + {2}^{3} - 9xyz \\ = {(3x)}^{3} + (y) + {2}^{3} - 9xyz \\ = {3x}^{3} + (y) + {2}^{3} + 3 \times 3xy \times z \\ \\ using \: identy \: \\ \\ {a}^{3} + {b}^{2} + {c}^{3} = (a + b + c) \\ ( {a}^{2} + {b}^{2} + {c}^{2} - ab - bc - ca) \\ \\ putting \: a = 3x \: b = y \: c = z \\ (3 \times + y + 2) \: 9 \times 2 \: + {y}^{2} + {2}^{2} - 3xy - yz - 3zx$