(y-1)x² (y 1)x (y-1)=0 x是实数则△≥0

由题意知因为x+y-a=0,x-2y=5所以解得X=（5+2a）/3,Y=（a-5）/3又因为x＞1,y≤1所以-1

∵y1与3x成正比例y2与（x+5）成正比例∵y1=k1×3xy2=k2(x+5)（k1k2≠0）∵y=2y1-y2=6k1-k2（x+5）∴12=6k1-6k2-2=-6k1-4k2∴k1=1k2=

,y1与x-1成正比例,y2与x正比例可设y1=k(x-1),y2=tx则y=y1-y2=k(x-1)-tx当X=2时,y=4;当x=-1时,y=-5则4=k-2t-5=-2k+t解得k=2,t=-1

设y1＝k1x，y2=k2（x-2），则y＝k1x−k2(x−2)根据题意，得k1+k2＝−1k13−k2＝5解得：k1=3，k2=-4∴y＝3x+4x−8当x=5时，y=35+20−8＝1235．

因为y1与x成正比例,y2与x减1成正比例所以可设y1=ax,y2=b(x-1)则y=ax+b(x-1)将两个点的坐标代入有：a+b(1-1)=32a+b(2-1)=7解方程组得：a=3b=1所以y=

y1=m(x+1)y2=nx*x且y=y1+y2;当x=1,y=2时（将x=1,y=2代入式子中）y=y1+y2得到2=2m+n当x=0,y=2时y=y1+y2得到2=m+0m=2,n=-2所以y=2

y1与x成反比例:y1=n/xy2与x-2成正比例:y2=m(x-2)并且当x=3时,y=5:y=y1-y2=n/x-m(x-2)=n/3-m(3-2)=n/3-m=5当x=1时,y=-1:y=y1-

1、设y=ax-b(x-2)=（a-b)x+2b,则有5=3(a-b)+2b-1=a-b+2b解dea=1,b=-2y=3x-42、设AC与BD交予O点,由等腰梯形的对称性可知,OA=OD=√2/2A

Y1和X成反比例,可得：Y1=a/X;Y2和X的平方成正比例,可得：Y2=bX²;当X=-1时,Y=-5时,即：Y=-a-b=-5;当X=1时,Y=1时,即:Y=a-b=1解上两式可得：a=

y1与x^2成反比例,y1=m/x^2y2与x+2成正比例,y2=n(x+2)y=y1+y2=m/x^2+n(x+2)x=1时,y=9；x=-1时,y=59=m/1+n(1+2)=m+3n.(1)5=

设y1=kx²,y2=t/x则y=y1+y2=kx²+t/xx=1时y=k+t=3；x=-1时,y=k-t=1两式联立解得k=2,t=1所以y=2x²+1/x当x=-1/

y=2y1-3y2(1)依题意：设y1=k1x,y2=k2/x∴y=2y1-3y2=2k1x-3*k2/x……①将x=1代入①得：y=2k1-3k2=1将x=2代入②得：y=4k1-3k2/2=5化简

不妨设y1=k1/x,y2=k2*(x-1);则y=(2*k1)/x-k2*(x-1);将（2,3)、（-1、-6）代入,得：k1-k2=3-2*k1+7*k2=-6联立上式得：k1=3k2=0综上,

不难,初中生吧?设y1=k1/xy2=k2(x-2)x=1时y=y1-y2=k1+k2=-1x=3时y=y1-y2=k1/3-k2解得,k1=3,k2=-4;故有y=3/x+4x+8

设y1=k1/x,y2=k2x^2则y=y1-y2=k1/x-k2x^2把x=-1,y=-5代入,得-k1-k2=-5把x=1,y=1代入,得k1-k2=1两式相加得-2k2=-4,k2=2k1=k2

DRSVYGJ新年好答案是：y=（3/x）-2x²∵y1与x反比例,∴可设y1=m/x∵y2与x²成正比例.∴可设y2=nx²又∵y=y1-y2∴y=（m/x）-nx&s

设y1=k1*√x,y2=k2*(1/x^2);x=1时,y=y1+y2=k1+k2=11x=4时,y=y1+y2=2*k1+k2/16=6.5解得k1=3,k2=8y=3*√x+8/x^2x=9时,

设y1=k1x−1，y2=k2x+2，∴y=k1x−1+k2x+2，把x=1，y=1；x=2，y=1，别代入上式得1＝k231＝k1+k24，（1分）解之得k1=14，k2=3，（2分）∴y=14x−

根据题意得Y=y1+y2y2=A（1/x^2）y1=B(x-1)(A、B为待定系数)然后就开始联立Y=A（1/x^2）+B（x-1）当X=2时Y=1；x=1时Y=8可得A/4+B=1A-2B=8解得A

y1=k1xy2=k2/x²y=k1x+k2/x²x=1y=33=k1*1+k2/1²k1+k2=3.(1)x=-1y=11=k1(-1)+k2/(-1)²-k