Dad gave me about 50 problems to sharpen my skills for the up coming school year...

Im having a few problems....Please help

1. Find the period of the graph of the equation y=2sin(pi x-3)

2. Find all solutions to the equation cos x=-1

choices

a. x= pi n

b. x= 2pi n

c. x= pi/2+ pi n

d. x= pi + 2 pi n

3. Use the addition and subtraction formula to simplify cos(x+pi)

Ya'll are great thanks