Question

A) Evaluate : (2x-y)3 (using suitable algebraic identity)

Answer 1

Answer:

$\mathrm{Expand\:\left(2x-y\right)^3:\quad 8x^3-12x^2y+6xy^2-y^3}$

Step-by-step explanation:

$\mathrm{\left(2x-y\right)^3}$

$\mathrm{Apply\:Perfect\:Cube\:Formula:\quad \left(a-b\right)^3=a^3-3a^2b+3ab^2-b^3}$

$\mathrm{\left(2x-y\right)^3=\left(2x\right)^3-3\left(2x\right)^2y+3\cdot \:2xy^2-y^3}$

$\mathrm{=\left(2x\right)^3-3\left(2x\right)^2y+3\cdot \:2xy^2-y^3}}$

$\mathrm{=8x^3-12x^2y+6xy^2-y^3}$

Answer 2

Step-by-step explanation:

(2x-y)3

= (2x)3 - (y)3 -3× 2x ×y (2x-y)

= 8x3 - y3- 6xy (2x - y)

= 8x3 - y3 - 12x2 y + 6xy2