Question

8x cube minus bracket 2x minus y bracket close whole cube

Answer 1

$8 {x}^{3} - {(2x - y)}^{3} \\ = 8 {x}^{3} - ( {(2x)}^{3} - {(y)}^{3} - 3(2x)(y)(2x - y) \\ = 8 {x}^{3} - (8 {x}^{3} - {y}^{3} - 12 {x}^{2} y + 6x {y}^{2}) \\ = 8 {x}^{3} - 8 {x}^{3} + {y}^{3} + 12 {x}^{2} y - 6x {y}^{2} \\ = {y}^{3} + 12 {x}^{2} + 6x {y}^{2}$
hope it helps you... please mark my answer as brainliest ☺️

Answer 2

8x^3-(2x-y)^3

a^3-b^3=(a-b)(a^2+ab+b^2)

where a=2x, b=2x-y

(2x)^3-(2x+y)^3

(2x-2x+y){4x^2+2x(2x-y)+(2x-y)^2}

y{4x^2+4x-2xy+4x^2+y^2-4xy}

y(8x^2+4x-6xy+y^2)

8yx^2+4xy-6xy^2+y^3

y^3+8yx^2-6xy^2+4xy

........:-)