Latest general Aptitude Question SOLUTION: If (x/y)+(y/x)=-1, then x^3-y^3= ?

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(#M40010805) GENERAL question Keep an EYE

If (x/y)+(y/x)=-1, then x^3-y^3= ?

Asked In general Devendra Marghade (11 years ago)

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kaamini sharma  (11 years ago)

x^2+y^2=(-xy)
x^3-y^3=(x-y)(x^2+y^2+xy)
so, =(x-y) (-xy+xy)
=(x-y)* 0
=0

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PARAG KAMRA  (11 years ago)

formula for a^3-b^3=(a-b)(a^2+b^2+ab)
same for
x^3-y^3=(x-y)(x^2+xy+y^2)
take common xy on R.H.S
x^3-y^3=(x-y)xy((x/y)+1+(y/x))................(1)
but given in question is that (x/y)+(y/x)=-1 (given)
so put this value in eq(1),we get
x^3-y^3=(x-y)xy(-1+1)
=0
so x^3-Y^3=0,If (x/y)+(y/x)=-1(ans)

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Raj  (11 years ago)

Formula is x^3-y^3 = (x-y)(x^2+xy+y^2)
= xy(x-y)((x/y)-1+(y/x))
=xy(x-y)(0)(bcz putting value given in question)
=0

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