Given this arithmetic sequence, what is a7 2,4,6,8,

An arithmetic sequencewe need a common number to add to each term to find the next term. The number is called the common difference and can be found by subtracting the first term from the second term. So the common difference is (4 - 2) = 2. What this means is when u add 2 to each erm, u get the next term.

an = a1 + (n - 1) * d
n = term to find = 7
a1 = 1st term = 2
d = common difference = 2
now we sub and solve
a7 = 2 + (7 - 1) * 2
a7 = 2 + 6 * 2
a7 = 2 + 12
a7 = 14 < this is a7

The discount is 8.70 . you dont tell us the percent of tax added so there is no way to find out, unless i'm not seeing anything. without tax its 37.70