x-0.2y=y-0.25x,-搜答案-百度作业网

x+x+x+y+y=54,x+x+y+y+y=56得出3X+2Y=54,2X+3Y=56扩大后得出6X+4Y=108,6X+9Y=118两式相减得出Y=2得出X=50/3

(x+y-z)(x-y+z)=

[x+(z-y)][x-(z-y)]=x-(z-y)记得采纳啊

令a=x+2yb=3x-ya/2+b/3=5(1)0.2a+0.8b=4(2)所以a=20-4b代入(1)10-2b+b/3=55b/3=5b=3a=20-4b=8所以x+2y=8(3)3x-y=3(

(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

x(x-y)+y(y-x)=x(x-y)-y(x-y)=(x-y)(x-y)=(x-y)²明教为您解答,请点击[满意答案];如若您有不满意之处,请指出,我一定改正!希望还您一个正确答复!祝您

X=2.85Y=2.6

y'-2y=(e^x)-x

首先求齐次方程通y'-2y=0特征方程：x-2=0x=2为特征根∴y=Ce^(2x)设方程的一个特解为y=Ae^x+ax+b代入方程：Ae^x+a-2Ae^x-2ax-2b=-Ae^x-2ax+a-2

令a=x²+y²则a²-a=12a²-a-12=0(a-4)(a+3)=0a=4,a=-3平方数大于等于0所以a=-3不成立所以x²+y²=

x+x+x+y+y+y+y+x=52+364(x+y)=88x+y=22x+x+x+y=522x+22=522x=30x=15y=22-xy=22-15y=7

x+y=5; x^y+y^x=17

X=2,Y=3或X=3,Y=2

求y'=y/(y-x)

∵令y=xt,则y'=xt'+t代入原方程,得xt'+t=t/(t-1)==>xt'=(2t-t^2)/(t-1)==>(t-1)dt/(2t-t^2)=dx/x==>2dx/x+[1/t+1/(t-

X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1

因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

先一个一个的展开括号项,再同项合并就行了啊[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x=[xx-xy-(xy-yy)+x(x-y)+y(x-y)]÷2x=[xx-xy-xy+yy+xx-

y'+2y/x=x通解

{(x,y) |x|+|y|

区域是一个正方形

x=0.25+yx+x+y=8.32(0.25+y)+y=8.33y=7.8y=2.6x=2.6+0.25=2.85x=2.85y=2.6

假设：X=Y/XY=X/Y带入函数就是：F(y/x,x/y)=（y/x+x/y）/(y/x—x/y)=x²+y²)/(y²-x²)希望可以帮助你!

x>y?x:y

判断X的数值是否大于Y的数值如果是则为真等式去X的值反之取Y的值

) y=cos(x-y)

1.两边求导得：y'=-sin(x-y)(1-y')解得y'=sin(x-y)/[sin(x-y)-1]2.y'=-e^-xy''=e^-xy'"=-e^-x3.y'"=(e^2x)'"(sinx)+