4X 9Y 7X-6Y=20
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移项、得1.5y=-3系数化为一、y=-2很简单的呀
2y+5/3y-6-y/2=5y-4/2y-42y+5/3y-1/2y-5y+2y=6-41/6y=2y=12
由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y
{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由(1)*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36
x²+4x+y²+6y+13=x²+4x+4+y²+6y+9=(x+2)²+(y+3)²=0所以x+2=0;y+3=0所以x=-2,y=-3
X^2+Y^2-2X+4Y=20.(1)(X-Y)^2+6X-6Y+8=0(X-Y)^2+6X-6Y+8=0(x-y)^2+6(x-y)+8=0(x-y+4)(x-y+2)=0x-y=-4,y=x+4
6y+12/y^2+4y+4-y^2-4/y^2-4y+4+y^2/y^2-4=0没有说明分母是那个分子是那个这样子很混乱建议加括号扩住分子分母再问:我现在加了括号再答:解6(Y+2)/(Y+2)^2
(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90)=x-2x-3x-4x-..-10x+y*(1-1/2-1/6-1/12-..1/90
第二个方程是不是写错了2/(x+y)+3/(x-y)=6是这样吗
(y+4)/5+y+6=(y+8)/2-(y+4)/3乘以30得6(y+4)+30y+180=15(y+8)-10(y+4)6y+24+30y+180=15y+120-10y-406y+30y-15y
6y-(y+2分之y+2-y分之y)除以y³-4y-2y²+8分之y=6y-[(2y-y²+2y+y²)/(4-y²)]÷y/(y-2)³=
题意不清什么是平方,*吗?那么**代表三次方还是4次方呢
3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2
2y+5/3y-6-y/2=5y-4/2y-42y+5/3y-1/2y-5y+2y=6-41/6y=2y=12再问:是2y+5/3y—1/2y—5y+2y=6—4吗再答:是的,绝对正确的,刚刚有一位同
题目是这样的:(X+Y)/2+(X-Y)/3=6(1)4(X+Y)-3(X-Y)=-20(2)将(1)两边同时乘以6得3X+3Y+2X-2Y=36→5X+Y=36(3)将(2)化解为4X+4Y-3X+
这两个均采用了配方法y=x²-4x+6=x²-4x+4+2=(x-2)²+2>=2y=-x²-2x+18=-(x²+2x+1)+19=-(x+1)
绝对值和平方式都是非负数,即大于等于零.因为这两个非负数的和为零,则它们只能为零.所以得到方程组6x+5y-25=0,3x+4y-20=0.解得x=0,y=5
题目有误(1)若是(3y+5)/(3y-6)=1/2+(5y-4)/(2y-4),(3y+5)/(3y-6)=1/2+(5y-4)/(2y-4)两边同时乘以12(y-2),得(3y+5)x4=12(y
完整设1/(x+y)=a,1/(x-y)=b原方程组可变为4a+6b=39b-a=1a=9b-136b-4+6b=3b=1/6,a=1/2x+y=2x-y=6所以原方程组的解为:x=4,y=-2
设u=x+y,v=x-y先解u/2+v/3=6,4u-3v=-20得u=4,v=12即x+y=4,x-y=12所以x=8,y=-4再问:我想问的是哪里有U再答:设出来的。另解,原方程组即5x+y=36