y =3x-1 x-2(x-3)的值域-搜答案-拍题作业网

x=1/3y=1/2x-(x+y）+（x+2y)-(x+3y)+...-(x+13y)=6y-13y=-7y=-7/2=-3.5

2x-3y=0(1)3x-y-1=0(2)由（2）得y=3x-1(3)把y=3x-1代入(1)得2x-9x+3=0∴x=3/7把x=3/7代入（3）得y=2/7∴x=3/7y=2/7

设a=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)那么y=a*(x-10);那么y^=a^*(x-10)+a*(x-10)^=a^*(x-10)+a那么y

[(2/3)x√(9x)+6x√(y/x)]+[y√(x/y)-x²√(1/x)]化简：原式=[(2/3)*3*x√x+6√(xy)]+[√(xy)-x√x]=2x√x+6√(xy)+√(x

可以化简为X到1.2.3...一直到十的距离你画个X轴就出来了可以很明显的得到1和10的中点5.5与1到10的距离和最小所以函数的最小值为25

(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

3x-4y/2x+y=1/26x-8y=2x+y4x=9yx/y=9/4

原试=-y-y-y.-y大概有50个-y所以答案是-50/3

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：

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

=（x-(x+y)）+（(x+2y)-(x+3y)）+...+(（x+98y）-(x+99y)）=-y*50=2*50=100

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

原式=(x-y)²-3(x-y)+1=3²-3×3+1x-y用3代替=1再问：3X+3Y是怎么转化成这个的3(X-Y)，什么理由再答：是-3x+3y不是3x+3y

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

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

y=2x2;-4x+2-3=2(x-1)2;-30≤x≤3-1≤x-1≤2所以0≤(x-1)2;≤40≤2(x-1)2;≤8-3≤2(x-1)2;-3≤5所以值域[-3,5]

把x=9y带入到3x=2y+1中得到3*(9y)=2y+127y=2y+125y=1y=1/25x=9y=9/25所以x=9/25,y=1/25

(x-2y)/(x+2y)=3取倒数(x+2y)/(x-2y)=1/3所以原式=(1/3)[(x-2y)/(x+2y)]-3[(x+2y)/(x-2y)]=(1/3)×3-3×(1/3)=0

-2x+3y=3x-2y+13y+2y=3x+2x+15y=5x+15y-5x=1y-x=1/5∴y＞x谢谢采纳满意请采纳