Question

Система {y^2+xy=231
x^2+xy=210

Answer 1

y(y+x)=231
x(x+y)=210

y/x=11/10
y=11/10x
x^2+x*11/10x=210
x=10
x=-10
y^2+10y=231
y^2-10y=231
y=11
y=-21
y=21
y=-11