Question

5. (X-Y)3(whole squar) in expanded form can be written as:
(a)X3 - Y3 +3XY(X-Y)
(b) X3-Y3-3XY(X+Y)
(c)x3 + 3x2Y-3XY2 - Y3
(d) X3-3x2Y +3XY2-Y3
​

Answer 1

Answer:

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