The given system of equations is equivalent to y2=2x/(1+x2),2(x−1)2+1+y3=0.
Since 2x/(1+x2)≤1 for all real x, it follows from the first of these equations that y2≤1 or −1≤y≤1.
Again from the second equation of the system, we get
y3=−1−2(x−1)2≤−1
Now since y≤−1 and y≥−1, we must have y=−1
Then x=1. This the solution is x=1, y=−1.