3x+5y=19 4x-3y=6 解方程组
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用换元法,设x+y=s,x-y=t,则原方程组为,s/2+t/3=6,①4s-5t=2,②将①×15+②,得,23s/2=92解得s=8,t=6即x+y=8,x-y=6两式加,得,x=7,y=1所以方
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=6①4(x+y)-5(x-y)=2②①*8得4(x+y)+8/3(x-y)=48③③-②得(8/3+5)(x-y)=46解得x-y=6④把x-y=6带入②解得x+y=8
2(x+2y)=x²+y²+5整理得(x-1)^2+(y-2)^2=0x=1,y=2(x²+y²)/(3x-4y)=-1
3x^2(x-y)+6x(y-x)=3x^2(x-y)-6x(x-y)=(x-y)(3x^2-6x)=3x(x-y)(x-2)
可以得出x.x+y.y-6x-8y+25=x.x-6x+9+y.y-8y+16=(x-3).(x-3)+(y-4).(y-4)=0因为(x-3).(x-3)>=0,(y-4).(y-4)>=0所以x=
2(2x+3y)(3x+2y)-(6x-y)(2x-5y)=12x^2+26xy+12y^2-(12x^2-32xy+5y^2)=12x^2+26xy+12y^2-12x^2+32xy-5y^2=58
3*(4x+3y)=124*(3x+5y)=-24下式减去上式,得:11y=-36,则y可解,再带入原方程求出X
(y-x)(x-y)^3(y-x)^5=(y-x)[-(y-x)^3](y-x)^5=-(y-x)^(1+3+5)=-(y-x)^9=(x-y)^9
(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90)=x-2x-3x-4x-..-10x+y*(1-1/2-1/6-1/12-..1/90
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-y)^5*(y-x)^3*(x-y)^2=-(x-y)^5*(x-y)^3*(x-y)^2=-(x-y)^(5+3+2)=-(x-y)^10
绝对值加平方=0因为两者均大于等于0所以都是0|x+y+2|=0(2x+3y+5)²=0x+y=-22x+3y=-5x=-1y=-1有什么不明白可以继续问,随时在线等.
=exp1,exp2------r=exp2逗号表达式从左往右执行,但返回的最后1个式子的值所以:y=((x=3*y,x+6),x-1);-->y=(x=x+6,x-1)-->y=(x=20,13)-
x-5y=13(1)3x+y=20(2)(1)+(2)*5x-5y+15x+5y=13+10016x=113x=113/16y=20-3x=-19/16
(3x-4y)(5x-4y)-(7x-8y)(6y-5x)=15x²-12xy-20xy+16y²-(42xy-35x²-48y²+40xy)=15x²
①×2-②得,-7y=5,解得y=-57,代入①得,x-3×(-57)=5,解得x=207.故原方程组的解为x=207y=−57.再问:非常感谢
(2X-3y)-(5x-y)=2x-3y-5x+y=2x-5x-3y+y=(2x-5x)+(-3y+y)=-3x-2y这样写总是全过程了吧
x+3y+|3x-y|=192x+y=6可知y=6-2x:代入上式可得x+3(6-2x)+|3x-(6-2x)|=19化简计算后可知:|5x-6|=1+5x可知5x-6=1+5x或5x-6=-(1+5