已知x加y等于3,xy=1求代数值5x加2-3xy
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X+Y=5,XY=2,5X+4Y-3X-2Y+XY=2X+2Y+XY=2(X+Y)+XY=2×5+2=12.
(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
∵(x+1)²+|y-2|=0 ∴x+1=0 y-2=0 ∴x=-1 y=2 ∴x²y²+3xy-7x²y²-(5/2)xy+1+5x²
1/x+1/y=3(3x+xy+3y)/(x—xy+y)上下同除以xy=(3/y+1+3/x)/(1/y-1+1/x)=(9+1)/(3-1)=5
分子分母同除以xy,分子变为2(1/x+1/y)+3=2x3+3=9分母变为(1/x+1/y)+2=3+2=5答案是9/5
xy分之x加y等于2∴x+y=2xy3x减5xy加3y分之负x加3xy减y=[-(x+y)+3xy]/[3(x+y)-5xy]=(-2xy+3xy)/(6xy-5xy)=xy/(xy)=1
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
再问:2/5再答:?
学了一元二次方程了吗?
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
直接设X=1,Y=0.5.带入后式得出10
已知A=x³+2y³-xy²,B=-y³+x³+2xy²,其中x等于1\3,y等于2A-B=(x³+2y³-xy
y-x-2xy=0(3x+xy-3y)/(y-xy-x)=(3x+6xy-5xy-3y)/(y+xy-2xy-x)=[-3(y-x-2xy)-5xy]/(y-x-2xy)+xy=(0-5xy)/(0+
此题简单做法你直接可以设X=1,Y=0.5,使其满足前面的条件即可,带入后面分式,后面的式子中文表述不清,
此题分多种情况讨论.当3-y的绝对值等于0时,x+y=1,y=3x=-2当3-y的绝对值等于1时,x+y=0y=2x=-2最后再带进去就OK了
3x-4y=4xy=13/y-4y=43-4y^2=4y4y^2+4y-3=0y=1/2,x=2;y=-3/2,x=-2/3所以当y=1/2,x=23x+4y=8当y=-3/2,x=-2/33x+4y
因为1/x+1/y=-3所以(x+y)/xy=-3即x+y=-3xy所以(x-6xy+y)/(3x+2xy+3y)=(-3xy-6xy)/[3(x+y)+2xy)]=-9xy/(-9xy+2xy)=9
(x+y)^2=x∧2+y∧2+2xy=9x∧2+y∧2=9-2×(-9)=27
已知xy/(x+y)=2,求:(3x-5xy+3y)/(-x+3xy-y)xy/(x+y)=2得:xy=2(x+y)(3x-5xy+3y)/(-x+3xy-y)=(3x-9xy+3y+4xy)/(-x