y=(x-6.5)2 (x-5.9)2 (x-6.0)2 (x-6.7)2

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计算:2x-{-3y+[3x-2(3x-y)]},其中x=-1,y=-1/5.

2x-{-3y+[3x-2(3x-y)]}=2x+3y-[3x-2(3x-y)]=2x+3y-3x+6x+2y=5x+5y当x=-1,y=-1/5时5x+5y=5*(-1)+5*(-1/5)=-5-1

6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5

设x-y=mx+y=n则6m-2n=143m+n=5解得m=2n=-1即x-y=2x+y=-1解得x=1/2y=-3/2

x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20

由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y

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

{(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20

{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由(1)*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36

y=(x^2+x)/(x+1)

这样算,分离变量:x²+x=(x+1)²-(x+1)然后,除下来,就等于x+1-1=x注意,x≠-1!

数学题已知p=x^/x-y-y^/x-y,q=(x+y)^-2Y(X+Y),

你的题是什么意思?“^/”是什么意思?

1、x(x-y)(x+y)-x(x+y)^2

1)x(x-y)(x+y)-x(x+y)^2=x((x-y)(x+y)-(x+y)^2)=x(x^2-y^2-x^2-2xy-y^2)=x(-2xy-2y^2)=-2xy(x+y)2)(2a+b)(2

求(x+y)(x-y)-(x-y)的二次方,的值.其中x=5.y=2

(x+y)(x-y)-(x-y)的二次方=(x-y)(x+y-x+y)=2y(x-y)=2*2*(5-2)=12

已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y

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

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)

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

[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013

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-

变量x,y满足x-2y=0,x

令a=2x-y,b=x+y用ab表示不等式,有4/3a-2/3b=01/3(a+b)

先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y

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

y=ln(x^2+e^x) 求Y'X

如果是求导数的话,y'=(2x+e^x)/(x^2+e^x)

解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7

展开x^2-2y^2-xy=-5x^2-2y^2+xy=7所以x^2-2y^2=1xy=6上式除以下式,解分式方程x/y=3/2或-4/3(舍去)所以x^2=9y^2=4x=3y=2或x=-3y=-2