✨ Best Answer ✨
x+y=1より、(x+y)^2=1 →①
①の式を展開して、x^2+y^2+2xy=1 →②
x^2+y^2=5より②に代入して、
2xy=-4
よってxy=-2
Answers
Were you able to resolve your confusion?
Users viewing this question
are also looking at these questions 😉
✨ Best Answer ✨
x+y=1より、(x+y)^2=1 →①
①の式を展開して、x^2+y^2+2xy=1 →②
x^2+y^2=5より②に代入して、
2xy=-4
よってxy=-2
Users viewing this question
are also looking at these questions 😉
分かりやすく解説していただきありがとうございます