Question

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

Answer 1

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 !