The first equation is

$\displaystyle 75*\sin{x}+5=0$

I tried solving it:

$\displaystyle \sin{x}=\frac{-5}{75}$

$\displaystyle x1 = -3.82^{\circ} + 360K$

$\displaystyle x2 = 183.82^{\circ} + 360K$

But the book says it's

$\displaystyle x1 = -45.58^{\circ} + 360K$

$\displaystyle x2 = 225.58^{\circ} + 360K$

The second equation looks more simple and I can solve it with my calculator but I want to know how to solve it without my calculator

$\displaystyle \sin{3x} = 1$

Thank you