xy分之2加x平方减x分之x 3除以x平方减2x 1分之x平方y 2xy减3y-搜答案-智慧作业帮

x/y=3x=3y(x^2+y^2-xy)/(x^2-y^2)=(9y^2+y^2-3y^2)/(9y^2-y^2)=7y^2/8y^2=7/8

2x²-3xy+y²=0(2x-y)(x-y)=0y=2x或y=x当y=2x时：y分之x+x分之y=xy分之(x²+y²)=(2x²)分之(x

∵(x+1)²+|y-2|=0　∴x+1=0　　y-2=0　∴x=-1　　y=2　∴x²y²+3xy-7x²y²-(5/2)xy+1+5x²

解法一,由已知y分之x等于7分之2,得x等于7分之2y.再把x等于7分之2y代入2x的平方减3xy加7y的平方分之x的平方减3xy加2y的平方,分子和分母合并同类型后,约去y的平方.解法二,2x的平方

-1/3(x^2y^2-xy+3)+2(x^2-1/2(xy-2x+y-1)+3x-1=-x^2y^2/3+xy/3-1+2x^2-xy+2x-y+1+3x-1=-x^2y^2/3-2xy/3+2x^

X=3y代入后面的公式

x减1分之x平方减1,化简为x+1得2005+1=2006第二问不太清楚

﹙x²－4y²﹚/﹙x²＋2xy＋y²﹚÷﹙x＋2y﹚/﹙2x²＋2xy﹚＝﹙x－2y﹚﹙x＋2y﹚/﹙x＋y﹚²·2x﹙x＋y﹚/﹙x＋2

x平方+y平方+2xy分之x平方-4y平方除以x平方+xy分之2y+x=(x-2y)(x+2y)/(x+y)²·x(x+y)/(x+2y)=x(x-2y)/(x+y)

x方+y方+5/4=2x+y(x方-2x+1)+（y方-y+1/4)=0(x-1)方+（y-1/2)方=0x=1,y=1/2xy/(x+y)=1/3

x(x-1)-(x^2-y)=-2x^2-x-x^2+y=-2x=y+2(x/2)^2+y^2-xy=((y+2)^2/4)+y^2-(y+2)y=y^2-4y+4

如果问题写清楚一些就好啦

3∵x/y=1/2∴y=2x故（x^2+2xy+y^2)/(x^2-xy+y^2)=(x+y)^2/(x^2-xy+y^2)=(x+2x)^2/(x^2-x·2x+4x^2)=9x^2/(3x^2)=

(x+3y)/(x²+xy)+(y-x)/(xy+y²)=(x+3y)[x(x+y)]-(x-y)/[y(x+y)]=[(x+3y)y-x(x-y)]/[xy(x+y)]=(xy+

X减Y减1分之X的平方减2XY加Y的平方减1=(x^2-2xy+y^2-1)/(x-y-1)=((x-y)^2-1)/(x-y-1)=(x-y+1)(x-y-1)/(x-y-1)=x-y+1

x²-7xy+12y²=(x-4y)(x-3y)=0x=4y或x=3yx=4y时(x²-xy+y²)/2xy=(16-4+1)y²/8y²=

(3x²+2xy-x/2)-(2x²-xy+x)=x²+3xy-3x/2