If x+y+z=1, xy+yz+zx=-1 and xyz=-1, find the value of (x^3+y^3+z^3).
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Using identity x3 + y3 + z3 - 3xyz = (x + y + z)(x2 + y2 + z2 - xy - yz - zx) = (3x + y + z)(9x2 + y2 + z2 - 3xy - yz - 3zx)
and (x+y+z)^2= x^2+y^2+z^2 +2(xy+yz+zx)
Using identity x3 + y3 + z3 - 3xyz = (x + y + z)(x2 + y2 + z2 - xy - yz - zx) = (3x + y + z)(9x2 + y2 + z2 - 3xy - yz - 3zx)
and (x+y+z)^2= x^2+y^2+z^2 +2(xy+yz+zx)
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