Question

The value of $(2y-x{)}^3$ is _________.

• A. $8y^3-x^3-12y^{2}x-12y{x}^2$
• B. $8y^3-x^3-12y^{2}x+6y{x}^2$
• C. $9y^3-x^3-12y^{2}x+6y{x}^2$
• D. $4y^3-x^3-12y^{2}x+6y{x}^2$

Answer 1

The correct option is B

$8y^3-x^3-12y^{2}x+6y{x}^2$

$(2y-x{)}^3$

Use the formula : $(a-b{)}^3$ = $a^3-b^3-3a^{2}b+3a{b}^2$

Here, $a=2y$, $b=x$

$(a-b{)}^3$ = $(2y-x{)}^3$ = $(2y{)}^3-(x{)}^3-3(2y{)}^{2}x+3(2y)x^2$

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