we are in C^3 .
(S): { ((x+y+z=2i−1 and xyz=2)),((xy+yz+xz=−2(1+i) )) :}
P(z)=z^3 +(1−2i)z^2 −2(1+i)−2.
show that (a,b,c) is solution
of (S) if and only a;b;c are
roots of P.
we define in base x the
number y and z by:
y=123^(−) ^(x ) and z=201^(−) ^x
1) without knowing x, write
the product x×y×z in function
of x.
2) we suppose that x+y+z=92
find x;y;z.