returned

s1+s2+s3=b/a *x+c/a *z+a/b *x+c/b *y+a/c *z+b/c *y

=(b/a *x+a/b *x)+(c/b *y+b/c *y)+(a/c *z+c/a *z)

=(b/a+a/b)*x+(c/a+a/c)*z+(c/b+b/c)*y lớn hơn hoặc bằng 2*x+2*y+2*z=2*(x+y+z)=2*5=10

suy ra ĐPCM

\(\frac{0,8^5}{0,4^6}=\frac{0,8^5}{0,4^5.\left(0,4\right)}=\left(\frac{0,8}{0,4}\right)^5.\left(0,4\right)=32.\left(0,4\right)=\frac{64}{5}\)\(\frac{0,8^5}{0,4^6}=\frac{0,8^5}{0,4^5.\left(0,4\right)}=\left(\frac{0,8}{0,4}\right)^5.\left(0,4\right)=32.\left(0,4\right)=\frac{64}{5}\)

Hi ban, rat vui duoc lam quen hjjjj
 

có vì 

a//b, c//a   => c//b