当x=-2,y=2 3时拍照
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设y=2^x,当x>0时,y的取值范围是y>1,当x
(x+y)(x-y)+(x-y)2-(x2-3xy),=x2-y2+x2-2xy+y2-x2+3xy,=x2+xy,当x=2,y=12时,原式=22+2×12=5.
x+y/x-y=1/2取倒数x-y/x+y=2所以x-y/x+y-2x+2y/x-y=x-y/x+y-2(x+y/x-y)=2-2×1/2=2-1=1
当x=-2时y=-1当x
∵二次函数y=2x2-x中对称轴为x=-b2a=--12×2=14,开口向上,∴当x>14时y随x增大而增大,当x<14时,y随x增大而减小,故答案为:x>14,x<14.
原式=1/2×2x-y/x+y+2x-y/6x-3y=1/2+1/3=5/6
(2x-y)/(x+y)=3所以(x+y)/(2x-y)=1/3原式=1/2*(2x-y)/(x+y)+1/3*(x+y)/(2x-y)=3/2+1/9=29/18
因为X+2/X-Y=2所以X=2Y+2将X=2Y+2代入X+Y/3(X-Y)-(X-Y)/2(X+Y)=(3Y+2)/3(2Y+2-Y)-(2Y+2-Y)/2(3Y+2)接下来自己算
当x=1时,y=0当x=-3时,y=0即x=1或-3是方程ax²+bx+c=0的两根即a(x-1)(x+3)=0即y=a(x-1)(x+3)=a(x²+2x-3)又当x=2时,y=
当x=1时,y=2代入2=a+b+c……(1)当x=-1时,y=-2代入-2=a-b+c……(2)当x=2时,y=33=4a+2b+c……(3)由(1)(2)(3)得出a=-1/3b=2c=1/3当x
原试=-y-y-y.-y大概有50个-y所以答案是-50/3
当x=y时2x+3y=2x+3x=45x=4x=4/5
当x为+∞或者无限接近于0的左边的,y为无穷大当x为无限接近于0的右边时或者x为无穷小时
当x/k=y时,x与y成(正)比例;当k/x=y时,x与y成(反)比例;当kxy=2时,x与y成(反)比例;当k/x=1/y时,x与y成(正)比例风雨兼程学海同舟有事说话
2x-y\x+y=32x-y=3(x+y)2x-y=3x+3y3x-2x=-y-3yx=-4y2x-y/2x+2y+x+y/6x-3y=(-8y-y)/(-8y+2y)+(-4y+y)/(-24y-3
1.(x+y)/(x-2y)=3x+y=3x-6y2x=7y2x/y=7y/y=72.16的(2-x)次方=8的(x+5)次方【16=2的4次方,8=2的3次方】2的4(2-x)次方=2的3(x+5)
=(x-(x+y))+((x+2y)-(x+3y))+...+((x+98y)-(x+99y))=-y*50=2*50=100
(x^4-y^4)/(x^2-2xy+y^2)÷(x^2+y^2)/(y-x)=(x^2-y^2)(x^2+y^2)/(x^2-2xy+y^2)*(y-x)/(x^2+y^2)=(x^2-y^2)/(
原式=(x-y)/x/((x^2-2xy+y^2)/x)=(x-y)/x乘以(x/(x^2-2xy+y^2))=(x-y)/x乘以(x/(x-y)^2)=1/(x-y)当x=2008,y=2009原式