22.已知x+y+z≠0x+y+z\ne 0x+y+z=0,aaa、bbb、ccc均不为0,且xy+z=a\frac{x}{y+z}=ay+zx=a,yx+z=b\frac{y}{x+z}=bx+zy=b,zx+y=c\frac{z}{x+y}=cx+yz=c,则a1+a+b1+b+c1+c=\frac{a}{1+a}+\frac{b}{1+b}+\frac{c}{1+c}=1+aa+1+bb+1+cc=[ 1 ]