Please help me with these equation and proofing,l was unable to solve it.

.)Solve the equation sin(x+170) cos(x-120) =0.7, for 0≤x≤3600

2.) Prove that sin 3x+sin2x 3x+2x/2 cos3x-2x/2

3.) Find all values x such that 0≤x≤3600 by solving cos2 x+sinx-3=0

4.) If sina=3/5 and cosb=9/41, find the values of sin (a-b),aand b being acute angle