Question

Решите систему x+y=3
X^2-xy-y^2=1

Answer 1

x+y=3X^2-xy-y^2=1

х=3-у
(3-у)²-у(3-у)-у²=1
9-6у+у²-3у+у²-у²=1
у²-9у+8=0
у1=1
у2=8

х1=3-1=2
х2=3-8=-5