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Question
Simplify:
\[\frac{8 x^3 - 27 y^3}{4 x^2 - 9 y^2}\]
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Solution
It is known that,
a2 − b2 = (a + b) (a − b)
a3 − b3 = (a − b)(a2 + ab + b2)
\[\ \frac{8 x^3 - 27 y^3}{4 x^2 - 9 y^2}\]
\[ = \frac{\left( 2x \right)^3 - \left( 3y \right)^3}{\left( 2x \right)^2 - \left( 3y \right)^2}\]
\[ = \frac{\left( 2x - 3y \right)\left[ \left( 2x \right)^2 + \left( 2x \right) \times \left( 3y \right) + \left( 3y \right)^2 \right]}{\left( 2x + 3y \right)\left( 2x - 3y \right)}\]
\[= \frac{\left(2x - 3y \right)\left(4 x^2 + 6xy + 9 y^2 \right)}{\left( 2x + 3y \right)\left(2x - 3y \right)}\]
\[= \frac{4 x^2 + 6xy + 9 y^2}{\left(2x + 3y \right)}\]
RELATED QUESTIONS
Simplify:
\[\frac{m^2 - n^2}{\left( m + n \right)^2} \times \frac{m^2 + mn + n^2}{m^3 - n^3}\]
Simplify:
\[\frac{x^2 - 5x - 24}{\left( x + 3 \right)\left( x + 8 \right)} \times \frac{x^2 - 64}{\left( x - 8 \right)^2}\]
Simplify:
\[\frac{3 x^2 - x - 2}{x^2 - 7x + 12} \div \frac{3 x^2 - 7x - 6}{x^2 - 4}\]
Factorise:
8p3 −\[\frac{27}{p^3}\]
Factorise:
64x3 − 729y3
Factorise:
`16a^3 - 128/b^3`
Simplify:
(x + y)3 − (x − y)3
Simplify:
(3xy − 2ab)3 − (3xy + 2ab)3
Factorise: 54p3 - 250q3.
Factorise the following:
27x3 – 8y3
