Question

Solve the expression: (2x – 7y)³

$\left[2Marks\right]$

Answer 1

Given: (2x – 7y)³.

As we know, (a-b)³ = a³-3a²b+3ab²– b³

Here, a = 2x and b = 7y

By substituting the values in the algebraic identity, we get

(2x – 7y)³ = (2x)³ – 3(2x)²(7y) + 3(2x)(7y)² – (7y)³
$\left[1Mark\right]$

(2x -7y)³ = 8x³ – 84x²y +294xy² – 343y³

Therefore, (2x – 7y)³ = 8x³ – 84x²y +294xy² – 343y³.
$\left[1Mark\right]$