已知x y等于a试求(x y)(2x 2y)的2次方(3x 3y)的2次方的值
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(2X-3Y-2XY)-(X-4Y+XY)=2X-3Y-2XY-X+4Y-XY=X+Y-3XY因为x加y等于110,xy等于33所以原式等于:110-33*3=11
由 1/X-1/Y=5,两边同乘 XY,得出Y-X=5XY,那么 分子 -X+XY+Y=6XY分母 2X+7XY-2Y=7XY-2(Y-X)=-3XY 得此分式的值为-再问:还有一题x+x分之一=
答:1/x+1/y=3(x-2xy+y)/(2x+xy+2y)分子分母同除以xy得:=(1/y-2+1/x)/(2/y+1+2/x)=(3-2)/(3*2+1)=1/7
C=-(A+B)=-(2x^2+3xy-2x+(-)x^2+xy-1)=-x^2-4xy+2x+2x^2表示x的平方
因为x+y除以xy等于4,所以,x+y=4xy2x-5xy+2y=2(x+y)-5xy=2*4xy-5xy=3xyx+2xy+y=4xy+2xy=6xy所以,2x-5xy+2y除以x+2xy+y的值=
XY除于X加Y等于3,则XY=3(X+Y)2X-3XY+2Y的和除于-X+3XY-Y=2X-9(X+Y)+2Y的和除于-X+9(X+Y)-Y=-7(X+Y)÷8(X+Y)=-7/8再问:是除于X+Y的
处理这类比例问题,有一个通用方法如果:x:y:z=a:b:c可以设x=aky=bkz=ck带入计算,就行了自己来试试吧~
x分之1-y分之1=4(xy)分之(y-x)=4y-x=4xyx-y=-4xy(x-2xy-y)分之(2x+xy-2y)=[(x-y)-2xy]分之[2(x-y)+xy]=(-4xy-2xy)分之(-
1/X-1/Y=4Y-X=4XY(2X+XY-2Y)/(X-2XY-Y)=[2(X-Y)+XY]/[(X-Y)-2XY]=7/6
x/y=3x=3yx²+2xy-3y²/x²-xy+y²=(3y)²+2*3y*y-3y²/(3y)²-3y*y+y²=
通分1/x-1/y=(y-x)/xy=3y-x=3xyx-y=-3xy原式=[(x-y)-2xy]/[5(x-y)+3xy]=(-3xy-2xy)/(-15xy+3xy)=-5xy/(-12xy)=5
∵x2+xy=-3,xy+y2=7,∴(x2+xy)+(xy+y2)=-3+7=4,即x2+2xy+y2=4.
A=(12xy-10xy²-2xy²)÷(-4xy)=(-12xy²-12xy)÷(-4xy)=3y+3即多项式A=3y+3
因为1/x-1/y=3所以方程左边先通分得y/xy-x/xy=3即(y-x)/xy=3所以得y-x=3xy(这一步很关键,一会要用整体代入法)要求的分数的分子:x+xy-y=xy-3xy=-2xy(因
2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3(x+y)+2xy=3*(-2)+2*3=0
由已知条件可得:x-y=-4xy,(也就是在等式两边乘xy后整理,即可),代入所求的式子里分母为-4xy+7xy,即3xy;分子为-4xy-2xy,即-6xy,化简得-2
ab互为相反数,a+b=0xy互为倒数,xy=1c的绝对值等于4,c=±4(a+b)/2+xy-(c/4)=0+1±1=0或2
y-x=3xyx-y=-3xyx-2xy-y=-5xy2x+3xy-2y=2(x+y)+3xy=-6xy+3xy=-3xy分式x-2xy-y分之2x+3xy-2y=5/3
x2+2xy-3y2=x2-xy+3xy-3y2=x2-xy+3(xy-y2),∵x2-xy=3,xy-y2=-5,∴x2+2xy-3y2=3+3×(-5)=-12.
设x+y=axy=b,则b/a=3b=3a所以-X+3XY-Y分之2X-3XY+2Y可以写成(2a-3b)/(3b-a)=-7/8