3 x=4 y=0和2(x=y)-3(2y-x)=62的解(引入参数)
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∵(3x-y-4)2+|4x+y-3|=0,∴3x−y=4①4x+y=3②,①+②得:7x=7,即x=1,将x=1代入①得:3-y=4,即y=-1,则x=1,y=-1.
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
设x/y=a,则y/x=1/a∵(2x-y)/3y=y/x∴2x/3y-1/3=y/x∴2a/3-1/3=1/a两边同时乘以3a2a²-a=3a²-a/2=3/2(a-1/4)
3x=4Y.X/Y=4/3,x-y)/y=(X/Y)-1=1/3,(3x+2y)/(2x+3y)=(4Y+2y)/(8/3y+3y)=18/17(因为3x=4Y,2x=8/3y)再问:若3X-4Y=0
很多数学符号,还是写出来方便.
{(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
化简得:-x+7y=11①7x+3y=27②①式×7得:-7x+49y=77③②+③得:52y=104∴y=2代入①得:x=3∴x=3,y=2再问:亲,是代入法哦!再答:代入法①式得3x+3y-4x+
(1)显然,y=0是原方程的解当y≠0时,∵y'+4y+y^2=0==>dy/dx=-y(y+4)==>dy/(y(y+4))=-dx==>[1/(y+4)-1/y]dy=4dx==>ln│y+4│-
3x+4y=2可知x=(2-4y)/3y=(2-3x)/4分别代入x-y5/7x
请将同一根号下的式子用括号括起来.因为根式不小于0,又因为两个根式相加等于0,所以两个根式分别等于0.即:x+2y=0……(1)3x-2y+4=0……(2)将(1)(2)相加得4x+4=0,所以x=-
3x^2+xy-2y^2=0推出(3x-2y)(x+y)=0推出x=-y或x=(2/3)y{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}/x^2-9y^2推出:{
第二个方程是不是写错了2/(x+y)+3/(x-y)=6是这样吗
X^2表示平方X^2+4X+4+Y^2-2Y+1=0(X+2)^2+(Y-1)^2=0因为平方大于=0所以X+2=0Y-1=0X=-2Y=1X^2+Y^2=5
即(x-2y)²=0x-2y=0所以x=2y所以原式=(2x²+2xy-xy-y²)/(4x²-4xy+y²)=(2x²+xy-y²
3x/2+5y-12=0①5x-4y/3+14=0②①×4+②×15得出x=-2,y=3
3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2
3X+4Y=23X=2-4YX=(2-4Y)/3X-Y-1/7D
因为|3x+2y-4|+√(2x-y-5)=0所以3x+2y-4=0(2x-y-5)=0解得x=2,y=-1
(x+y)/2+(x-y)/6=1x/2+x/6+y/2-y/6=12x/3+y/3=12x+y=3(1)3(x+y)-4(x-y)=43x+3y-4x+4y=4-x+7y=4(2)(1)+2*(2)
我把方法告诉你,最后的答案你自己做吧,很容易.(x+y)(x+2y)(x+3y)(x+4y)=-40(x+y)(x+4y)(x+2y)(x+3y)=-40(x^2+5yx+44)(x^2+5yx+66