已知y=3-4x分之x-2,x哪些取值时

x=y+3∴x-y=34分之一(x-y)的平方-0.3(x-y)+0.75(x-y)的平方+10分之3(x-y）-2（x-y）+7=(0.25+0.75)(x-y)²+(-0.3+0.3-2

2x-y分之x+y=2,则2x-y=2(x+y)4x-2y分之x+y-4x+4y分之2x-y=2(2x-y)分之x+y-4(x+y)分之2x-y=4(x+y)分之x+y-4(x+y)分之2(x+y)=

x+y分之4x-2y-2x-y分之4x+4y=2(2x-y)/(x+y)-4(x+y)/(2x-y)=2*2-4*(1/2)=4-2=2

2/3

解原式=2(x-y)/(x+y)-(x+y)/3(x-y)=6(x-y)(x-y)/[3(x+y)(x-y)]-(x+y)x+y)/[3(x-y)(x+y)]=5(x-y)(x-y)/[(x+y)(x

x+3y分之4x-2y-2x-y分之4x+12y=2(2x-y)/(x+3y)-4(x+3y)/(2x-y)=2*2-4*1/2=4-2=2

因为x+y分之2x-y=2又因为x+y分之4x-2y是它的2倍所以x+y分之4x-2y就=4因为x+y分之2x-y=2倒过来2x-y分之x+y就为1/2又2x-y分之4x+4y是2x-y分之x+y的4

设二分之x=三分之y=二分之一分之z=k则x=2ky=3kz=2kx+3y-z分之2x-y+z=9k分之3k=1/3

∵（2x+y)/2=(5x+2y)/4=1∴{2x+y=2(1){5x+2y=4(2)(1)==>y=2-2x代入（2）5x+2(2-2x)=4x+4=4,∴x=0,y=2∴(x+2y+1)/(2x-

x+y分之x-y=2求x+y分之3x-3y减x-y分之2(x+y)的值x+y分之x-y=2x-y=2(x+y)(x+y)分之(3x-3y)-(x-y)分之2(x+y)的值x+y分之3x-3y=(x+y

由于|x+y|≠x+y,说明x+y0则x+y=-12又4分之3+8又2分之1=-51/4+17/2=-17/4即负4又四分之一2.若y

(3x-4y)÷(2x+y)=1/2所以2x+y=2(3x-4y)=6x-8y4x=9y所以x/y=9/4

因为：3分之x+1=4分之y+3=5分之x+y,所以：（x+1）/3=（y+3）/4=(x+y)/54x+4=3y+94x=3y+55x+5=3x+3y2x=3y-5x=5y=5则x+2y+3分之3x

y=4x带入3x-y=3x-4x=-xx+y=x+4x=5x(x+y)/(3x-y)=5x/(-x)=-5

5x=-3yx=-3|5y直接带进去得答案,或者=2\3x-2|3x+2|x+y的和乘（x+y）除以x-y|x=2乘x\x-y=2（-3\5y）\（-3\5y-y）=3\4手机果然不行.

X=3Y+4/5Y-2则X（5Y-2）=3Y+45XY-2X=3Y+4(5X-3)Y=2X+4则Y=2X+4/5X-3

因为x＋y/2=3x＋4y/5=1,所以x＋y=2,3x＋4y=5所以解方程组得x=3,带入x＋5y＋6/3x－y＋1,得4/11

x/3-y/4=3x+2y==>4x-3y=36x+24y==>①32x=-27y==>x=-27y/32②(4x-3y)^2=(36x+24y)^2②==>16x^2+9y^2-24xy=1296x

原式等价于10(x+1)=5(y+3)=4(x+y)10(x+1)=5(y+3)可得2x-y=15(y+3)=4(x+y)可得4x-y=15解得x=7y=13x+2y+3=363x+2y+1=48两式

1.整理得到算式[2x-x+y]/[x^2-y^2]=[x+y]/[x+y][x-y]=1/[x-y]代入得到1/72.整理得到[1-3/(a+2)]/[(a^2-2a+1)/(a^2-4)]=[(a