The straight line \(l_1\) has equation \(2x + y - 14 = 0\) and crosses the \(x\)-axis at the point \(A\).
- Find the coordinates of \(A\). [2]
The straight line \(l_2\) is parallel to \(l_1\) and passes through the point \(B(-6, 6)\).
- Find an equation for \(l_2\) in the form \(y = mx + c\). [3]
The line \(l_2\) crosses the \(x\)-axis at the point \(C\).
- Find the coordinates of \(C\). [1]
The point \(D\) lies on \(l_1\) and is such that \(CD\) is perpendicular to \(l_1\).
- Show that \(D\) has coordinates \((5, 4)\). [5]
- Find the area of triangle \(ACD\). [2]