[tex]a_{3} = 14 \\ 14 = a_{1} + (3 - 1)r \\ 14 = a_{1} + 2r \\ \\ a_{11} = 34 \\ 34 =a_{1} + (11 - 1)r \\ 34 = a_{1} + 10r \\ \\ 14 = a_{1} + 2r \\ 34 = a_{1} + 10r \\ \\ a_{1} = - 2r + 14 \\ 34 = - 2r + 14 + 10r \\ \\ a_{1} = - 2r + 14 \\ 34 - 14 = 8r \\ \\ a_{1} = - 2r + 14 \\ 20 = 8r \\ \\ a_{1} = - 2r + 14 \\ r = \frac{5}{2} \\ \\ a_{1} = - 2 \times \: \frac{5}{2} + 14 \\ r = \frac{5}{2} \\ \\ a_{1} = - 5 + 14 \\ r = \frac{5}{2} \\ \\ a_{1} =9 \\ r = \frac{5}{2}[/tex]
