A curve has equation \(y = x^2 + 2cx + 4\) and a straight line has equation \(y = 4x + c\), where \(c\) is a constant.
Find the set of values of \(c\) for which the curve and line intersect at two distinct points.
A curve has equation \(y = kx^2 + 2x - k\) and a line has equation \(y = kx - 2\), where \(k\) is a constant.
Find the set of values of \(k\) for which the curve and line do not intersect.
It is given that the equation \(16x^2 - 24x + 10 = k\), where \(k\) is a constant, has exactly one root.
Find the value of this root.