解方程组0.6x-0.5y=2.7,1.8x+y=0.6
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x-2y=0①x²+3y-3y²=4②由(1)得:x=2y(3)代入(2)得:4y²+3y-3y²=4y²+3y-4=0(y+4)(y-1)=0y1=
(1)×1212x+24y=18(3)(2),12x+12y+15y=20,12x+27y=20(3)-(2)12x+24y-12x-27y=18-207y=-2y=-7/2代入(1),x+2×(-7
3x+y=k①x+3y=2②②乘以3,得3x+9y=6③③减去①,得8y=6-ky=(6-k)/8将y=(6-k)/8代入②中,得x+3(6-k)/8=2x=2-3(6-k)/8因为x,y
y=3(x-y),x=2(x-y)x=0y=0再问:请问,怎样解=0,要过程,谢谢再答:y=3(x-y)=3x-3y4y=3xy=3x/4x=2(x-y)=2x-2y=2x-3x/2=x/2x-x/2
0.2X+0.3Y=4.6(1)0.7X-0.5Y=0.6(2)(1)×5+(2)×3得:x+2.1x=23+1.8;3.1x=24.8;x=8;带入(1)得:1.6+0.3y=4.6;0.3y=3;
一会上手写稍等再问:OK再答:
/>X/0.5+Y/0.2=20①X/10+Y/2=2/3②由①得:2X+5Y=20③由②×10得:X+5Y=20/3④由③-④得:X=40/3把X=40/3代入③得:80/3+5Y=205Y=-20
0.6x-0.5y=2.7(1),1.8x+y=0.6(2)(1)×2+(2)得:3x=6;x=2;带入(1),y=-3;
合并方程组:x+y/2=3x-2y;3x-2y=10+6x+y/4;得出:x=5y/4;从而算出:x=-25/12,y=-5/3.手机打很累.
(0.2x+0.1y)/2-(4x-y)/10=(x-y)/5+(3x+0.5y)/30①(3x+2y-1)/8=3-(0.8x-5y)/41②①两边同时乘以60得(6x+3y)-(24x-6y)=(
0.6x-0.4y=1.1①0.2x-0.4y=2.3②,①-②得,0.4x=-1.2,解得x=-3,把x=-3代入①得,0.2×(-3)-0.4y=2.3,解得y=-294,所以,方程组的解是x=-
{3x-4y(x-y)=3,2x-3y=12x-3y=1,得x-y=(1+y)/23x-4y(x-y)=3,代入x-y=(1+y)/2,得3x-2y(1+y)=33x-2y-2y²=34y+
若3x>y则方程互相矛盾,所以3x<>y,解得x=9/10,y=21/5
x+y/3=x-y/4⑴2x+3y=11⑵由⑴得x+7y=0,x=-7y(3)将(3)代入⑵得y=-1所以x=7
解将x+y=3代入1/2(x+y)-3y=5∴1/2×3-3y=5∴3y=3/2-5∴3y=-7/2∴y=-7/6∴x=25/6
5x+8y=47(1)6x+12y=66(2)x+2y=11(2)'解出:x=11-2y代入(1)得到:5(11-2y)+8y=4755-10y+8y=472y=8y=4x=11-2*4=3即:x=3
y=x-3代入方程2y+3x-3y=112(x-3)+3x-3(x-3)=112x-6+3x-3x+9=112x=8x=4y=x-3=1
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
可能是0<X0=X0≤X≤1X>1当0<X时,|X+Y|=1原式=Y-X=1Y=1+X|X|+2|Y|=3变2(1+X)-X=3X=1所以Y=0当0=X时Y无解,不成立.当0≤X≤1时X+Y=1X+2
1.5x-0.5y=1乘以4得到6x-2y=42x+3y=5乘以3得到6x+9y=15相减得到11y=11所以y=1x=1