Question 5 - A-Level Maths

Show that the equation $\cos 2 x \left( \tan ^ { 2 } 2 x + 3 \right) + 3 = 0$ can be expressed as $$2 \cos ^ { 2 } 2 x + 3 \cos 2 x + 1 = 0$$
Hence solve the equation $\cos 2 x \left( \tan ^ { 2 } 2 x + 3 \right) + 3 = 0$ for $0 ^ { \circ } \leqslant x \leqslant 180 ^ { \circ }$.