ArticlesBlog Linear vs. exponential growth: from data | High School Math | Khan Academy December 16, 20193 Related tags : Education learning lessons online learning Post navigation Previous Article How to become an Office Secretary? Career Builder videos from funza Academy Next Article King’s Cup Derby Game for Free Download – Play Horseracing Mobile Phone Game! Comments (3) February 19, 2016 at 3:37 am how do you know it's 4t?? I thought it is 3t since the year gap is 3 years Reply February 19, 2016 at 5:47 am Just by looking at the table(left), we need a function that is equal to 34 branches when t=0 and has an average rate of change of 12 branches for every 3 years. So B(t)=34+4(t). This function is equal to 34 when t is 0 and adds 12 for every three years(t). B(3)=34+4(3)=34+12=46 B(6)=34+4(6)=34+24=58 B(6)-B(3)=58-46=12 So this function does increase by 12 branches for every 3 years, which is what we need since Sal calculated that the average increase in branches for every 3 years is 12 branches. Reply February 24, 2018 at 6:54 am omg what he s saying I didn't cach any thing its really confusing me 🙁 Reply Comment here Cancel reply Comment Name * Email * Save my name, email, and website in this browser for the next time I comment.