(y³z分之-3x)²
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设x=2K.Y=3k.Z=4kx-y+z分之x+y-z=(2k-3k+4k)分之(2k+3k-4k)=3k分之k=3分之1
设3分之x=2分之y=5分之z=t∴x=3t,y=2t,z=5tx-y+z分之2x-3y-z==(6t-6t-5t)/(3t-2t+5t)=-5t/6t=-5/6
x/2=y/3=z/0.5=2zx=4z,y=6z.(x+3y-z)/(2x-y+z)=(4z+18z-z)/(8z-6z+z)=21z/3z=7.望采纳!
设(x+y-z)/z=(x-y+z)/y=(-x+y+z)/x=k则(1)x+y-z=kz(2)x-y+z=ky(3)-x+y+z=kx(1)+(2)+(3)得x+y+z=k(x+y+z)∴k=1时,
设x/2=y/3=z/4=k则x=2ky=3kz=4k3x+2y-z分之x-y-z=(x-y-z)/(3x+2y-z)=(2k-3k-4k)/(3*2k+2*3k-4k)=(-5k)/(8k)=-5/
因为2x=3y=4z可得,x=2z,y=4/3z代入2x-y+z=11/3zx+y+z=13/3z2x-y+z分之x+y+z的值等于13/11
解由5分之x=4分之y=3分之z令5分之x=4分之y=3分之z=k则x=5k,y=4k,z=3kk不等于0则3x-2y分之x+y+z=(3x-2y)分之(x+y+z)=(3*5k-2*4k)分之(5k
设:k=3分之x=4分之Y=6分之Z则:x=3k,y=4k,z=6kX-Y+Z分之X+Y-Z=(3k-4k+6k)/(2k+4k-6k)=5k/k=5
2:=19y或12(2/3)x或19(3/4)z3:④>②>③>①再问:过程再答:2:代入未知数一步步倒3:设极值a的绝对值=1那么a=1或者-1同理,b=2或者-2,那四个数每个数都把a,b代入其中
令2分之x=3分之y=4分之z=k,则:x=2ky=3kz=4kx+y+z=1/12,得:2k+3k+4k=1/129k=1/12k=1/108所以:x=2/108=1/54y=3/108=1/36z
令(y+z)/x=(z+x)/y=(x+y)/z=ky+z=kxx+z=kyx+y=kz2(x+y+z)=k(x+y+z)2(x+y+z)=k(x+y+z)(2-k)(x+y+z)=0(x+y+z≠0
假设x分之3=y分之4=z分之5=1,则x=3,y=4,z=53x-2y+z分之x+y+z=(3x3-2x4+5)分之(3+4+5)=6分之12=2http://zhidao.baidu.com/li
因为x/3=y/4=z/5所以可令x=3k,y=4k,z=5k.(k不为0)所以带入得:(3x-2y+z)/(x+y+z)=1/2再问:为什么等于1/2--嗯题是x+y+z/3x-2y+z.....不
x:y:z=3:4:6设x=3a,y=4a,z=6a;其中a≠0原式=(3a+4a-6a)/(3a-4a+6a)=a/5a=1/5
令x/3=y/4=z/5=t则x=3t,y=4t,z=5t(x+2y+3z)/(2x+y-z)=(26t)/(5t)=26/5
因为2分之x=3分之y=4分之z,设2分之x=3分之y=4分之z=A,得X=2A,Y=3A,Z=4A(X+2Y-3Z)/(2X-Y+3Z)=-4/13
x:y:z=3:4:5=6,求x-y+z分之x+y-z的值3y=4x,y=4x/3,3z=5x,z=5x/3x-y+z分之x+y-z=(x-4x/3+5x/3)/(x+4x/3-5x/3)=(4x/3
解:不防设x=2A,则y=3A,z=5A.由x+y+z=20,可知2A+3A+5A=20,10A=20,A=2.则x=4,y=6,z=10.
设2分之x+y=3分之y+z=5分之x+z=k则x+y=2k,y+z=3k,x+z=5k3式相加得2(x+y+z)=10k=18*2=36,k=3.6,x+y+z=5kz=5k-2k=3k=10.8x