x+y+z=1
x^2+y^2+z^2=21
x^3+y^3+z^3=55
Square both sides,
By second equation we have,
Now, use the identity,
So,
Use equation 3,
Thus,
Thus, we have,
The solution to this are the roots of the polynomial, by Viete's Theorem.
Which solves nicely
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