因为a3=a1+2d,a9=a1+8d
所以(a1+2d)^2=a1(a1+8d)
故d^2=a1*d
因为公差d≠0
所以d=a1
所以a6=a1+5d=6d,a7=a1+6d=7d
故(a3+a6+a9)/(a4+a7+a10)=3a6/3a7=a6/a7=6d/7d=6/7
因为a3=a1+2d,a9=a1+8d
所以(a1+2d)^2=a1(a1+8d)
故d^2=a1*d
因为公差d≠0
所以d=a1
所以a6=a1+5d=6d,a7=a1+6d=7d
故(a3+a6+a9)/(a4+a7+a10)=3a6/3a7=a6/a7=6d/7d=6/7