помогите, с чего начать решение?

$5sin (11x)+4cos(3x)+3sin(3x)=0;\\\\ sin(11x)+\frac{4}{5}cos(3x)+\frac{3}{5}sin(3x)=0;\\\\ (sin \phi=\frac{4}{5}; cos \phi=\frac{3}{5}; \phi=arctg \frac{4}{3});\\\\ sin(11x)+sin \phi *cos(3x)+cos \phi *sin(3x)=0;\\\\ sin(11x)+sin(\phi+3x)=0;\\\\ 2sin(\frac{11x+\phi+3x}{2})cos(\frac{11x-\phi-3x}{2})=0;;\\\\ sin (7x+\frac{\phi}{2})cos(4x-\frac{\phi}{2})=0;\\\\ 7x+\frac{\phi}{2}=\pi*n;\\\\ 7x=-\frac{\phi}{2}+\pi*n;\\\\ x_1=-\frac{1}{14}arctg \frac{4}{3}+\frac{\pi*n}{7};\\\\$

$4x-\frac{\phi}{2}=\frac{\pi}{2}+\pi*k;\\\\\ 8x=\phi+\pi+2*\pi*k;\\\\ x_2=\frac{1}{8}arctg \frac{4}{3}+\frac{\pi}{8}+\frac{\pi*k}{4};$

n є Z

k є Z