Question

3x-2y=11, xy=12 find the value of 27x3-8y3​

Answer 1

Answer:

• Hi...☺
• Here is your answer...✌
• GIVEN THAT,
• 3x - 2y = 11 -----(1)
• xy = 12 -----(2)
• Cubing both sides in eq(1)
• We get
• (3x - 2y)³ = 11³
• (3x)³ - (2y)³ - 3(3x)(2y) (3x - 2y) = 11³
• 27x³ - 8y³ - 18xy × 11 = 11³ __ [from (1)]
• 27x³ - 8y³ - 18×12×11 = 11³ __ [from(2)]
• 27x³ - 8y³ = 11³ + 18×12×11
• = 11 (11² + 18×12)
• = 11 (121 + 216)
• = 11 × 337
• = 3707
• Hence,
• 27x³ - 8y³ = 3707