The line \(l_1\) passes through the point \((9, -4)\) and has gradient \(\frac{1}{3}\).
- Find an equation for \(l_1\) in the form \(ax + by + c = 0\), where \(a\), \(b\) and \(c\) are integers. [3]
The line \(l_2\) passes through the origin \(O\) and has gradient \(-2\). The lines \(l_1\) and \(l_2\) intersect at the point \(P\).
- Calculate the coordinates of \(P\). [4]
Given that \(l_1\) crosses the \(y\)-axis at the point \(C\),
- calculate the exact area of \(\triangle OCP\). [3]