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Artist 52 [7]
3 years ago
8

If 3x - 2y = 9 , 27x³- 8y³= 1377 , prove that xy = 4 plzz answer this question... ​

Mathematics
1 answer:
solniwko [45]3 years ago
8 0

Step-by-step explanation:

Here we are given that , the Value of

  • 3x - 2y = 9
  • 27x^3 - 8y^3 = 1377

And we need to find the prove that ,

  • xy = 4

We know a identity as ,

  • (a-b)^3 = a^3-b^3-3ab(a-b)

On cubing both sides of the given equation,

  • (3x-2y)^3 = 9^3

Simplify and then substitute ,

  • 27x^3-8y^3 -3(3x)(2y)(3x-2y ) = 729

  • 1377 - 18xy (9) = 729

  • 162xy = 1377-729

  • xy =\dfrac{648}{162}

  • xy = 4

Hence Proved !

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