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=1/20
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?
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
(x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3.
2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=2
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{6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1
变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y
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若x*x+y*y=x+y-1/2,求x,y的值如题
y'/y=1/x
先化简,再求值:y(x-y)-x(x+y)/x²-y²÷x²+y²/x+y,其中x=2,y=-1