(a)[4]
Solve the equation $3\tan^2 x - 5\tan x - 2 = 0$ in the interval $0^\circ \leq x \leq 180^\circ$.
(b)[2]
Find the values of $k$ for which $3\tan^2 x - 5\tan x + k = 0$ has no solutions.
(c)[3]
For $3\tan^2 x - 5\tan x + k = 0$, state the value of $k$ that gives three solutions in the interval $0^\circ \leq x \leq 180^\circ$, and find those solutions.