Find the gradient of the line \(l\) which has equation \(x + 2 y = 4\).
Find the equation of the line parallel to \(l\) which passes through the point ( 6,5 ), giving your answer in the form \(a x + b y + c = 0\), where \(a , b\) and \(c\) are integers.
Solve the simultaneous equations
$$y = x ^ { 2 } + x + 1 \quad \text { and } \quad x + 2 y = 4$$