1tìm x,y,z
\(\frac{y+z+1}{x}=\frac{x+z+2}{y}=\frac{x+y-3}{z}=\frac{1}{x+y+z}.\)
\(\frac{x}{2}=\frac{y}{3}=\frac{z}{5},xyz=810\)
2tìm x:
\(\frac{1+2y}{18}=\frac{1+4y}{24}=\frac{1+6y}{6x}\)
3
\(CMRtừ:\frac{a+b}{a-b}=\frac{c+d}{c-d}\ne1\)
\(tacó:\frac{a}{b}=\frac{c}{d}\)
\(1+1=2\)
1+1=2
là sai