Question

125xcube + 729ycube factorise

Answer 1

125x³ + 729³

Here, we will solve the problem by using the formula of a³ + b³ = (a + b) (a² - ab + b²)


125 is the cube of 5 and 729 is the cube of 9

So,

=> (5x)³ + (9y)³

=> (5x + 9y) [(5x)² - (5x) × (9y) + (9y)²]

=> (5x + 9y) (25x² - 45xy + 81y²)



$\therefore{}$ 125x³ + 729³ = (5x + 9y) (25x² - 45xy + 81y²)

Answer 2

Here is your solution

Given:-

125x³ + 729³

Now,

we will solve the problem by using the formula

a³ + b³ = (a + b) (a² - ab + b²)

Our assumption

125 is the cube of 5 and 729 is the cube of 9

So now

=> (5x)³ + (9y)³

=> (5x + 9y) [(5x)² - (5x) × (9y) + (9y)²]

=> (5x + 9y) (25x² - 45xy + 81y²)

Hence

125x³ + 729³ = (5x + 9y) (25x² - 45xy + 81y²)