The 9th term of an arithmetic progression is 8 and the 4th term is 18.
Find the first term \(a\) and the common difference \(d\).
The 3rd term of an arithmetic progression is 1 and the 6th term is 10.
Find the 4th term.
In an arithmetic progression the 8th term is 39 and the 4th term is 19.
Find the first term \(a\) and the sum of the first 12 terms.
The sum of the terms of an arithmetic progression is 38.5.
The first term is 1 and the last term is 6.
Work out how many terms there are.
The nth term of an arithmetic progression is
\(u_n=\frac{1}{2}(7-n)\).
Write down the first three terms and the 20th term.