find value of 27x^3+8y^3 if 3x+2y=14 and xy= 8
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Answered by
0
3x+2y = 14
cube on both sides,
(3x+2y)^2 = 14^3
= 27x^3 +8y^3 +3(3x*2y)[3x+2y] = 2744
=27x^3 + 8y^3 + 18(8)[14] = 2744
=27x^3 + 8y^3 + 2016 = 2744
= 27x^3 +8y^3 = 2744 - 2016
=27x^3 +8y^3 = 728
i hope this will help you
- by ABHAY
cube on both sides,
(3x+2y)^2 = 14^3
= 27x^3 +8y^3 +3(3x*2y)[3x+2y] = 2744
=27x^3 + 8y^3 + 18(8)[14] = 2744
=27x^3 + 8y^3 + 2016 = 2744
= 27x^3 +8y^3 = 2744 - 2016
=27x^3 +8y^3 = 728
i hope this will help you
- by ABHAY
Answered by
0
27x³+8y³= (3x)³ + (2y)³
= (3x+2y)³-3(3x*2y)(3x+2y)
= (14)³-3(6*8)(14)
= 2744 - 2016
= 728
= (3x+2y)³-3(3x*2y)(3x+2y)
= (14)³-3(6*8)(14)
= 2744 - 2016
= 728
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