Question

Expand (2c-3d)3 pls say this answer

Answer 1

(2c-3d)³

Using Identity (a-b)³ = a³ - b³ - 3a²b + 3ab²

Here , a = 2c and b = 3d

Therefore , (2c-3d)³

= (2c)³ - (3d)³ - 3 × (2c)² × 3d + 3× 2c × (3d)²

= 8c³ - 27d³ - 3× 4c² × 3d + 3× 2c × 9d²

= 8c³ - 27d³ - 36c²d + 54cd²

Other important Identities :

• (a+b)² = a² + b² + 2ab

• (a-b)² = a² + b² -2ab

• a² - b² = (a+b) (a-b)

• (a+b+c)² = a² + b² + c² +2ab + 2bc +2ca

• (a+b)³ = a³ + b³ +3a²b + 3ab²

Answer 2

$\huge\sf\blue{ANSWER}$

GIVEN:-

• Expand $(2c-3d)^3$

Identity Used:-

• $(a-b)^3=a^3-b^3-3×a×b(a-b)$

• a=2c, b=3d

Now,

$(2c-3d)^3=(2c)^3-(3d)^3-3×2c×3d(2c-3d)$

$8c^3-27d^3-36c^2d+54cd^2$

$\mathbb{EXTRA\:INFORMATION}$

• $(a+b)^2=a^2+b^2+2ab$

• $(a-b)^2=a^2-2ab+b^2$

• $a^3-b^3=(a-b) (a^2+ab+b^2)$