The fourth one is just a basic one you need to use the formula V=pi* ...so you see that you need to find the zeros of so either x=0 or =0 so x=0 or x= 2 by graphing you will see that you need to set up two integrals since [-2,0] the graph is below the x-axis and from [0,2] its above so what you do is apply the formula v=pi* so V in this case is equal to pi* +pi* =well I will leave that up to you

the other ones when you revolve it around a vertical axis I'd use shell method which is V=2 where h(x) is the the distance from the axis to any point in the region you are revolving and g(x) is your curve