若1 x-1 y=2,则3a 4xy-3y 2x-xy-2y的值为多少
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用图像法,画x>=-1;y>=x;3x+2y
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))
解析x+y-1=0y=-3所以x=4x+y=1平方根是-1和1
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==>
(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
2x-y-3=3x+2y+1=0,x=5/7,y=-11/7
2x*X+3y*y=1,S=3x*x-2y*yS=3x*x-2((1-2x*x)/3)=13*x*x/3-2/32x*X+3y*y=1,即X*X/(1/2)+y*y/(1/3)=1这是一个椭圆其中a=
2X+3Y-1=X+62X+3Y=7(1)Y-X-8=X+62X-Y=-14(2)(1)+(2)4X+2Y=-7两边除以22X+Y=-7/2
由题意得:y-x-8=x+6,将其变形得:2x-y=-14.
3x+2y再问:不是哦,答案为3再答:不好意思,7是个错误答案。因为这样算下来就是x=y=-1,与结果矛盾。正解是:x
=(x^4+x^3y)+(y^4+xy^3)+(4x^3y+4x^2y^2)+(4xy^3+4x^2y^2)+x^2y+xy^2=x^3(x+y)+y^3(x+y)+4x^2y(y+x)+4xy^2(
解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy
7y(x-3y)²-2(3y-x)³=7y(x-3y)²+2(x-3y)³=(x-3y)²[7y+2(x-3y)=(x-3y)²(7y+2X
X+6=Y-X-8,所以2X-Y+14=0;Y-X-8=2X-3Y-1,所以3X-4Y+7=0;联立,可得X=-119/10;Y=-49/5再问:那3X-Y?再答:下面你不会吗?3X=-357/10,
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!
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
解析:若x²-3x=1,那么:x²y-3xy-y=y(x²-3x-1)=y(1-1)=0
x,y∈{-√3,-1,1,2}中只有(X,Y)∈{(1,1)(1,-1)(-1,1)(-1,-1)(-1,-√3)(-√3,-1))(1,-√3)(-√3,1)}可满足X^2+Y^2