Question

the model an=395n +5419 describes the cost of tution and fees at public colleges in academic year n, where n=1 corresponds to the school year ending in 2007,n=2 to the school year ending in 2008 and so on four years

use this and the formula for sn to find the total cost of tution and fees at public colleges for four years

Answer 1

`\boxed{a_n=395n+5419}\\ \\ a_4=395*4+5419\\ \\ a_4=1580+5419\\ \\ \boxed{\boxed{a_4=6,999}}`

Answer 2

Just substitute 4 in for n, then you would get 395*4 +5419. That is 6999, so it's 6999 for four years.