The first 14 terms of an arithmetic series are 21+34+47+60+⋯+177+x21 + 34 + 47 + 60 + \dots + 177 + x21+34+47+60+⋯+177+x.
Find the value of xxx.
Find the sum of these 14 terms.
326 exam-style questions on Edexcel A Level Maths Sequences and Series, covering 3.1 Arithmetic Sequences, 3.2 Arithmetic Series, 3.3 Geometric Sequences, 3.4 Geometric Series, 3.5 Sum to Infinity, 3.6 Sigma Notation, 3.7 Recurrence Relations, and 3.8 Modelling with Series. Each one has a worked solution and a mark scheme showing where the marks go.