Contact us
Choose a category below so we can get back to you as quickly as possible.
答: 設公差為d,則: a3-a2=d=3.1-2.8=0.3 a1=a2-d=2.8-0.3=2.5 a15=a1+14d=2.5+14*0.3=6.7 所以第15項為6.7.
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.