x x=y逗号外 y等于德语-搜答案-拍题作业网

(x-y)(x+y)(xx-yy)=?

(x-y)(x+y)(xx-yy)=(x^2-y^2)(x^2-y^2)=x^4-2x^2y^2+y^4

是12x39=468=6x78吗

X:Y:Z=1:2:3因为：14(XX+YY+ZZ)=(X+2Y+3Z)^214(XX+YY+ZZ)-(X+2Y+3Z)^2=013X^2+10Y^2+5Z^2-4XY-6XZ-12YZ=0(4X^2

函数y=xx

∵x＞0∴y=xx2+x+1=1x+1+1x又∵x+1x≥2x•1x＝2∴1y＝x+1x+1≥ 3，当且仅当x=1时等号成立∴0＜y≤13，即函数的值域为(0，13]故答案为：(0，13]

已知y＝xx

根据题意得，xx2−x÷x2−1x2−2x+1−2x+1＝13，xx(x−1)×(x−1)2(x−1)(x+1)-2x+1=13，-1x+1=13，解得x=-4，经检验x=-4是原方程的根；∴原方程的

x+y=5,xy=-3,则x^2y+xy^2=xy(x+y)=-3*5=-15

用基本不等式当15x=1470/x时y最大x为根号下98,即7倍根号2

(xx-4x+4)+|y-1|=0(x-2)^2+|y-1|=0x-2=0,y-1=0x=2,y=1(X/Y-Y/X)/(X+Y)=(2-1/2)/3=1/2

逗号运算符运算顺利是从左到右,先计算第一个表达式,再计算第二个,依此类推.将最后一个表达式的值作为整个表达式的值.：（y=6,y+1,x=y,x+1)先将6赋值给变量y,再将y+1的值作为表达式2的值

理解正确.

XX-YY/(X-Y)(X-Y)约分

XX-YY/(X-Y)(X-Y)=(x^2-y^2)/(x-y)(x-y)=(x+y)(x-y)/(x-y)(x-y)=(x+y)/(x-y)

2/9再问：过程，谢谢再答：由题目得y/x=2/3xy/xx+yy-yy/xx-yy=y/x-(y/x)²=2/3-4/9=2/9

xx+yy+4x-6y+13=0整理得：(x+2)^2+(y-3)^2=0那么只有(x+2)=0(y-3)=0x=-2y=3(x^2-2x)/(x^2+3y^2)=(4+4)/(4+3*9)=8/31

x^2+x-x^2-y=3x-y=3(x-y)^2=9x^2+y^2-2xy=9(x^2+y^2)/2-xy=9/2

(x+y)(x+y)=25x^2+2xy+y^2=25……(1)(x-y)(x-y)=9x^2-2xy+y^2=9……（2）（1）+（2）得：2x^2+2y^2=34x^2+y^2=17(1)-(2)

x(x+1)-(xx+y)=-3x^2+x-x^2-y=-3x-y=-3(xx+yy)/2-xy=(x^2+y^2-2xy)/2=(x-y)^2/2=(-3)^2/2=9/2再问：是对的吧！再答：当然

y+1=2/y等于什么

∴y²+y=2∴y²+y+1/4=2+1/4∴（y+1/2）²=4/9∴y+1/2=±2/3∴y=1或－2再问：用换元法解方程x^+x+1=2/x^+x时，若设x^+x=

xx-yy-x-y 因式分解

xx-yy-x-y=(x^2-y^2)-(x+y)=(x+y)(x-y)-(x+y)=(x+y)(x-y-1)

x y x+yy x+y xx+y x y

把所有列都加至第一列,第一列都是2x+2y将2x+2y提出,第一列剩下都是1,此时式外边有一因子（2x+2y）用2,3行加第1行负一倍得1yx+y0xy0x-y-x第一列展开得1*（-x^2-y(x-