tim cac so nguen x,y,z:x/y+y/z+z/x=y/x+z/y+x/z=x+y+z=3
Tim cac so nguyen x, y, z thoa man x/y +y/z+z/x =y/x+/y+x/z=x+y+z=3
Tim cac so nguyen x,y,z biet
x(x+y+z)=-5
y(x+y+z)=9
z(x+y+z)=5
Giải
Ta có : \(\hept{\begin{cases}x\left(x+y+z\right)=-5\\y\left(x+y+z\right)=9\\z\left(x+y+z\right)=5\end{cases}}\Rightarrow x\left(x+y+z\right)+y\left(x+y+z\right)+z\left(x+y+z\right)=-5+9+5\)
\(\Rightarrow\left(x+y+z\right)\left(x+y+z\right)=9\)
\(\Rightarrow\left(x+y+z\right)^2=3^2\)
\(\Rightarrow x+y+z=3\)
\(\Rightarrow\hept{\begin{cases}3x=-5\\3y=9\\3z=5\end{cases}}\Leftrightarrow\hept{\begin{cases}x=\frac{-5}{3}\\y=3\\z=\frac{5}{3}\end{cases}}\)
Mà x , y , z là các số nguyên nên không có nghiệm x , y , z cần tìm
Tim cac so nguyên x,y,z biet
x+y=2,y+z=3,x+z=-5
x= -3
y= 5
z= -2....đúng 100000%
tích cho mk ik mọi người....>.<!!!!
cho x,y,z la cac so thuc duong thoa man x+y+z=1 tim min A=x^3/(x^2+xy+y^2)+y^3/(y^2+yz+z^2)+z^3/(z^2+zx+x^2)
tim cac so huu ti x,y,z biet x+y=1/2 y+z=1/3 z+y=1/4
tim cac so m,n,p thoa man : m+n+p+8=2canm-1 + 4cann-2 +6canp-3
tim cac so x,y,z thoa man :canx+cany-1 +canz-2 = 1/2(x+y+z)
tim cac so x,y,z thoa man :x+y+z+4=2canx-2 +4cany-3+6canz-5
cho x,y,z la cac so thuc thoa x+y+z=0, x+1>0, y+1>0, z+1>0. tim GTLN cua P=\(\frac{x}{x+1}+\frac{y}{y+1}+\frac{z}{z+4}\)
cho x,y,z,t la cac so duong. tim GTNN cua A=\(\frac{x-t}{t+y}+\frac{t-y}{y+z}+\frac{y-z}{z+x}+\frac{z-x}{x+t}\)
tim cac so nguyen x ,y,z thoa man /x-y/+/y-z/+/z-x/=2015
tìm x,y,z:x/z+y+1=z/y+x+1=z/x+y-2