已知x^2 5Y^2-4XY 2Y 1
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![已知x^2 5Y^2-4XY 2Y 1](/uploads/image/f/4228296-24-6.jpg?t=%E5%B7%B2%E7%9F%A5x%5E2+5Y%5E2-4XY+2Y+1)
2x+3y=18(1)3x+4y=25(2)(1)×3,得6x+9y=54(3)(2)×2,得6x+8y=50(4)(3)-(4),得y=4将y=4代入(1),得2x+12=182x=6x=3所以x=
|2-x|+|x-y+4|=02-x=0,x-y+4=0x=2,2-y+4=0,y=63(x-y)-5(x-y)^2-3(x-y)+(y-x)^2+4(x+y)^2+3(y-x)=-4(x-y)^2+
x^2+y^2+4x-6y+13=(x+2)^2+(y-3)^2=0所以x=-2y=3所以x^y=-8
无解,题目错了
解题思路:先求出x,y再化简二次根式代入求值解题过程:最终答案:略
先化简[(x²+y²)-(x-y)²+2y(x-y)]/4y[(x²+y²)-(x-y)²+2y(x-y)]/4y=[x²+y&s
4x-2y=0→y=2x,把所有的y都用2x替代.结果是-1/7
原式=(2x-y)(x+y)/(2x-y)^2=(x+y)/(2x-y)x/y=2x=2y原式=3y/3y=1
3x-4y/2x+y=1/26x-8y=2x+y4x=9yx/y=9/4
X^2表示平方X^2+4X+4+Y^2-2Y+1=0(X+2)^2+(Y-1)^2=0因为平方大于=0所以X+2=0Y-1=0X=-2Y=1X^2+Y^2=5
即(x-2y)²=0x-2y=0所以x=2y所以原式=(2x²+2xy-xy-y²)/(4x²-4xy+y²)=(2x²+xy-y²
x平方+8x+16+y平方+6x+9=0(x+4)平方+(y+3)平方=0∴x+4=0y+3=0∴x=-4,y=-3原式=(x+2y)(x-2y)/(x+2y)平方-x/(x+2y)=(x-2y)/(
x²+4x+y²-2y+5=0x²+4x+4+y²-2y+1=0(x+2)²+(y-1)²=0所以x+2=0y-1=0则x=-2y=1所以x
x-2y/2x+3y=3/44(x-2y)=3(2x+3y)4x-8y=6x+9y-2x=17yx/y=-17/2
4x=9yx=9/4*y(1)(x+y)/y=[(9/4)y+y]/y=(9/4+1)y/y=9/4+1=13/4(2)(y-x)/2x=[y-(9/4)y]/[2*(9/4)y]=(1-9/4)y/
(x+y)²=x²+2xy+y²(x-y)²=x²-2xy+y²两式相加得(x+y)²+(x-y)²=2(x²
x/y=3/2则2x=3y带进去就变成6y-9y/(3y+3y)=-1/2y感觉怪怪的.一般都是转换下形式然后带进去这题怎么没一般项--或者直接将x=3y=2带进去
(x²-4x+4)+(4y²+8y+4)=0(x-2)²+4(y+1)²=0则:x-2=0且y+1=0得:x=2、y=-1x+y=1
1,-3再问:过程。。。再答:★(x²-2x)+(y²-4y)=5★(x-1)²+(y-2)²=1+4-5★(x-l)²=0,(y-2)²=
原式=x-x+x-x+……-x+(2-1+4-3+5-4+……+2008-2007-2009)y=0+(1×1004-2009)y=-1005y=1005/2