pls answer this question as fast as possible!
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siddhartharao77:
I think the question is incomplete
really?
Yes
our teacher gave us only this much
what is the value of 4x - 5y?
16
ooops srry
Its okkkk
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Given Equation is (4x - 5y) = 16 and xy = 12.
(4x - 5y) = 16.
On cubing both sides, we get
(4x - 5y)^3 = (16)^3
We know that (a - b)^3 = a^3 - b^3 - 3ab(a - b).
(4x)^3 - (5y)^3 - 3(4x)(5y)(4x - 5y) = 4096
64x^3 - 125y^3 - 60xy(4x - 5y) = 4096
64x^3 - 125y^3 - 60(12)(16) = 4096
64x^3 - 125y^3 - 11520 = 4096
64x^3 - 125y^3 = 4096 + 11520
64x^3 - 125y^3 = 15616.
Hope this helps!
(4x - 5y) = 16.
On cubing both sides, we get
(4x - 5y)^3 = (16)^3
We know that (a - b)^3 = a^3 - b^3 - 3ab(a - b).
(4x)^3 - (5y)^3 - 3(4x)(5y)(4x - 5y) = 4096
64x^3 - 125y^3 - 60xy(4x - 5y) = 4096
64x^3 - 125y^3 - 60(12)(16) = 4096
64x^3 - 125y^3 - 11520 = 4096
64x^3 - 125y^3 = 4096 + 11520
64x^3 - 125y^3 = 15616.
Hope this helps!
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