Question

Solve this step by step:
If 3x-2y=4 and xy=5. Find the value of 27x^3-8y^3.​

Answer 1

Answer:

420

Step-by-step explanation:

3x - 2y = 4

doing cube on both sides

27x³ - 8y³ - 3 × 9x² ×2y + 3 × 3x × 4y² = 64

27x³ - 8y³ - 54x²y + 32y² = 64

27x³ - 8y³ - 18xy(3x - 2y ) = 64

using above values

27x³ - 8y³ - 18 × 5 × 4 = 64

27x³ - 8y³ - 360 = 64

27x³ - 8y³ = 360 + 64

27x³ - 8y³ = 420 ans