1-.1/x+1/y=1/20x+2y=3 2-.2√x+1=y+12x-3y=13-.x*y=122^2-5y^2=164-.x^2+y^2=82/9xy=-15-.√x=4-yy^2=4+x6-.x^2+y^2+2x=0x^2+y^2+y=0要考试了,搞不懂这几道题目.1.4.5.6没人会做吗?
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![1-.1/x+1/y=1/20x+2y=3 2-.2√x+1=y+12x-3y=13-.x*y=122^2-5y^2=164-.x^2+y^2=82/9xy=-15-.√x=4-yy^2=4+x6-.x^2+y^2+2x=0x^2+y^2+y=0要考试了,搞不懂这几道题目.1.4.5.6没人会做吗?](/uploads/image/z/811285-61-5.jpg?t=1-.1%2Fx%2B1%2Fy%3D1%2F20x%2B2y%3D3+2-.2%E2%88%9Ax%2B1%3Dy%2B12x-3y%3D13-.x%2Ay%3D122%5E2-5y%5E2%3D164-.x%5E2%2By%5E2%3D82%2F9xy%3D-15-.%E2%88%9Ax%3D4-yy%5E2%3D4%2Bx6-.x%5E2%2By%5E2%2B2x%3D0x%5E2%2By%5E2%2By%3D0%E8%A6%81%E8%80%83%E8%AF%95%E4%BA%86%2C%E6%90%9E%E4%B8%8D%E6%87%82%E8%BF%99%E5%87%A0%E9%81%93%E9%A2%98%E7%9B%AE.1.4.5.6%E6%B2%A1%E4%BA%BA%E4%BC%9A%E5%81%9A%E5%90%97%3F)
1-.1/x+1/y=1/20x+2y=3 2-.2√x+1=y+12x-3y=13-.x*y=122^2-5y^2=164-.x^2+y^2=82/9xy=-15-.√x=4-yy^2=4+x6-.x^2+y^2+2x=0x^2+y^2+y=0要考试了,搞不懂这几道题目.1.4.5.6没人会做吗?
1-.1/x+1/y=1/20
x+2y=3
2-.2√x+1=y+1
2x-3y=1
3-.x*y=12
2^2-5y^2=16
4-.x^2+y^2=82/9
xy=-1
5-.√x=4-y
y^2=4+x
6-.x^2+y^2+2x=0
x^2+y^2+y=0
要考试了,搞不懂这几道题目.
1.4.5.6没人会做吗?
1-.1/x+1/y=1/20x+2y=3 2-.2√x+1=y+12x-3y=13-.x*y=122^2-5y^2=164-.x^2+y^2=82/9xy=-15-.√x=4-yy^2=4+x6-.x^2+y^2+2x=0x^2+y^2+y=0要考试了,搞不懂这几道题目.1.4.5.6没人会做吗?
4. x²+2xy+y²=64/9
(x+y)²=64/9
x+y=±8/3
x²-2xy+y²=100/9
(x-y)²=100/9
x-y=±10/3
分段讨论:当 x+y=8/3 x-y=10/3时 x=3 y=-1/3
当 x+y=8/3 x-y=-10/3时 x=-1/3 y=3
当 x+y=-8/3 x-y=-10/3时 x=-3 y=1/3
当 x+y=-8/3 x-y=10/3时 x=1/3 y=-3
5. x=16-8y+y²
y²=4+16-8y+y²
y=5/2 ,x=9/4
6. y=2x
x²+4x²+2x=0
x=0或x=-2/5
y=0或y=-4/5