Please tell how to solve Q 18

Dear student, {(a + b + c)}^{3} = a^{3} + b^{3} + c^{3} + 3 (a + b) (b + c) (c + a) {(2 x - y + 2)}^{3} = (2 x)^{3} + {(- y)}^{3} + {(2)}^{3} + 3 (2 x - y) (- y + 2) (2 x + 2) = 8 x^{3} - y^{3} + 8 + 3 (- 2 xy + y^{2} + 4 x - 2 y) 2 (x + 1) = 8 x^{3} - y^{3} + 8 + 6 (- 2 x^{2} y + {xy}^{2} + 4 x^{2} - 2 xy - 2 xy + y^{2} + 4 x - 2 y) = 8 x^{3} - y^{3} + 8 + 6 (- 2 x^{2} y + {xy}^{2} + 4 x^{2} - 4 xy + y^{2} + 4 x - 2 y) = 8 x^{3} - y^{3} + 8 - 12 x^{2} y + 6 {xy}^{2} + 24 x^{2} - 24 xy + 6 y^{2} + 24 x - 12 y Regards

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