Question

factorise a^3 + a- 3a^2 - 3 ​

Answer 1

We have,

$\blue{ \longmapsto } \red{ {a}^{3} + a - 3 {a}^{2} - 3}$

$\blue{ = } {a}^{3} - 3 {a}^{2} + a - 3$

$\blue{ = } {a}^{2} (a) + {a}^{2} ( - 3) + 1(a) + 1( - 3)$

$\blue{ = } {a}^{2} (a - 3) + 1(a - 3)$

$\blue{ = } \green{(a - 3)( {a}^{2} + 1)}$