- (a) Find the sum of all the integers between 1 and 1000 which are divisible by 7 .
(b) Hence, or otherwise, evaluate \(\sum _ { r = 1 } ^ { 142 } ( 7 r + 2 )\). - Solve the simultaneous equations
$$\begin{gathered}
x - 3 y + 1 = 0
x ^ { 2 } - 3 x y + y ^ { 2 } = 11
\end{gathered}$$