若x(x-1)-(x^2 y)=6

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若变量x,y满足约束条件{x>=-1;y>=x;3x+2y

用图像法,画x>=-1;y>=x;3x+2y

若全集I={(x,y)|x,y∈R},集合M={(x,y)|(y-3)/(x-2)},N{(x,y)|y=x=1},则(

N={(1,1)},M={(x,y)|y-3=x-2},即M={(x,y)|y-x-1=0},CIM即为除直线外的所有的(x,y),CIN即为除(1,1)外的(x,y),所以(CIM)∩((CIM))

设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于

Dx^y+x^-y=2根号2===>(x^y+x^-y)^2=8===>x^2y+x^-2y+2=8===>x^2y+x^-2y=6(x^y-x^-y)^2=x^2y+x^-2y-2=6-2=4==>

若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值?

(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)=4x^2-y^2+2xy-8x^2-y^2+4xy+2y^2-6xy=-4x^2=-4(-1/4)^2=-1/4

若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y=

2x-y-3=3x+2y+1=0,x=5/7,y=-11/7

y=(x^2+x)/(x+1)

这样算,分离变量:x²+x=(x+1)²-(x+1)然后,除下来,就等于x+1-1=x注意,x≠-1!

若x-y=1,求代数式x(x-y)+y(y-x)+2013的值

因为X-Y=1所以原式=x*1+y*(-1)+2013=x-y+2013=1+2013=2014

x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2

x(x+y)(x-y)-x(x+y)2=x(x+y)[(x-y)-(x+y)]=x(x+y)(-2y)=-2xy(x+y)=-2×(-1/2)×1=1再问:18p3q3-2pq再答:7(x-1)3-1

1、x(x-y)(x+y)-x(x+y)^2

1)x(x-y)(x+y)-x(x+y)^2=x((x-y)(x+y)-(x+y)^2)=x(x^2-y^2-x^2-2xy-y^2)=x(-2xy-2y^2)=-2xy(x+y)2)(2a+b)(2

函数,y=3x/(x^2+x+1) ,x

y=3/(x+1/x+1)x+1/x≤-2,所以x+1/x+1≤-1令t=x+1/x+1,则t≤-1,y=3/t值域为[-3,0)再问:你写的我看不大懂再问:一步步写再答:

若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.

x+y=1x-y=2(x+2y)(x-2y)-(2x-y)(-y-2x)=(x+2y)(x-2y)+(2x-y)(y+2x)=x²-4y²+4x²-y²=5x&

(1)(x^2/x)-y-x-y

(1)x^2/x)-y-x-y=x-y-x-y=-2y(2)(a/a-b)-(a/a+b)-(2b^2/a^2-b^2)=a(a+b-a+b)/(a^2-b^2)-(2b^2/a^2-b^2)=2b/

先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y

解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy

{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1

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

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于

若(x-y)/(x+y)=3那么x-y=3(x+y)x-y=3x+3y故x=-2y所以(x+2y)/(6x-7y)=(-2y+2y)/(6*(-2y)-7y)=0如果不懂,请Hi我,祝学习愉快!

方程组2x+y=1-m...x+2y=2中,若未知数x,y满足x+y

两方程相加,得x+y=1-m/3因为x+y

若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7

x(x*x-1)+x(5-x*x)-6y+7=-x+5x-6y+7=2(2x-3y)+7=2*(-4)+7=-8+7=-1再问:能在写详一点吗-x+5x-6y+7再答:x(x*x-1)+x(5-x*x

函数y=3x/(x^2+x+1) (x

原式可以化为:y*x^2+(y-3)*x+1=0Δ=(y-3)^2-4y≥0解得y≥9或y≤1由于x

若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&

∵|x+2y-1|+y²+4y+4=0∴|x+2y-1|+(y+2)²=0∴x=5,y=-2(2x-y)²-2(2x-y)(x+2y)+(x+2y)²=[(2x