已知x、y为实数,且(x^+y^)(x^+y^+10)=20,求x^+y^的值要详细解答~ 把好意思哈打错了是已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)
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![已知x、y为实数,且(x^+y^)(x^+y^+10)=20,求x^+y^的值要详细解答~ 把好意思哈打错了是已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)](/uploads/image/z/7204838-14-8.jpg?t=%E5%B7%B2%E7%9F%A5x%E3%80%81y%E4%B8%BA%E5%AE%9E%E6%95%B0%2C%E4%B8%94%28x%5E%2By%5E%29%28x%5E%2By%5E%2B10%29%3D20%2C%E6%B1%82x%5E%2By%5E%E7%9A%84%E5%80%BC%E8%A6%81%E8%AF%A6%E7%BB%86%E8%A7%A3%E7%AD%94%7E+%E6%8A%8A%E5%A5%BD%E6%84%8F%E6%80%9D%E5%93%88%E6%89%93%E9%94%99%E4%BA%86%E6%98%AF%E5%B7%B2%E7%9F%A5x%E3%80%81y%E4%B8%BA%E5%AE%9E%E6%95%B0%2C%E4%B8%94%28x%5E%2By%5E%29%28x%5E%2By%5E%2B1%29%3D20%2C%E6%B1%82x%5E%2By%5E%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5x%E3%80%81y%E4%B8%BA%E5%AE%9E%E6%95%B0%2C%E4%B8%94%28x%5E%2By%5E%29%28x%5E%2By%5E%2B1%29%3D20%2C%E6%B1%82x%5E%2By%5E%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5x%E3%80%81y%E4%B8%BA%E5%AE%9E%E6%95%B0%2C%E4%B8%94%28x%5E%2By%5E%29)
已知x、y为实数,且(x^+y^)(x^+y^+10)=20,求x^+y^的值要详细解答~ 把好意思哈打错了是已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)
已知x、y为实数,且(x^+y^)(x^+y^+10)=20,求x^+y^的值
要详细解答~
把好意思哈
打错了
是
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值
已知x、y为实数,且(x^+y^)(x^+y^+10)=20,求x^+y^的值要详细解答~ 把好意思哈打错了是已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)(x^+y^+1)=20,求x^+y^的值已知x、y为实数,且(x^+y^)
(x^2+y^2)(x^2+y^2+1)=20
(x^2+y^2)^2+(x^2+y^2)-20=0
(x^2+y^2-4)(x^2+y^2+5)=0
x^2+y^2≥0
所以x^2+y^2=4
(x^+y^)(x^+y^+10)=20
(x^+y^)^2+10(x^+y^)=20
(x^+y^)^2+10(x^+y^)-20=0
(x^+y^)^2+10(x^+y^)+25-25-20=0
(x^+y^+5)^2-45=0
(x^+y^+5+3√5)(x^+y^+5-3√5)=0
x^+y^=-5-3√5(舍去 x^+y^≥0)
x^+y^=3√5-5
(x^+y^)(x^+y^+1)=20
(x^+y^)^2+10(x^+y^)-20=0
(x^+y^-4)(x^+y^+5)=0
x^+y^=4 (x^+y^=-5舍弃)
解:设x^2+y^2=k>0
则
k(k+1)=20
k^2+k-20=0
(k+5)(k-4)=0
k=-5或k=4
因为x^2+y^2>=0
所以x^2+y^2=4