Question

find the value plz ​

Answer 1

Answer:

305 is your answer

Step-by-step explanation:

Given that : -

(3x - 4y) = 5 and xy = 3

To find : - value of 27x³ - 64y³ = ?

Now,

----------

3x - 4y = 5

On squaring both sides, we have

(3x - 4y)² = (5)²

=> 9x² + 16y² - 24xy = 25

=> 9x² + 16y² = 25 + (24 × 3)

=> 9x² + 16y² = 25 + 72

=> 9x² + 16y² = 97

Then ,

27x³ - 64y³

= (3x)³ - (4y)³

= (3x - 4y)(9x² - 12xy + 16y²)

= 5 × {(9x² + 16y²) - (12 × 3)}

= 5 × (97 - 36)

= 5 × 61

= 305

HOPE IT HELPS