two algebra questions! please help :(

1)Given V = 2πr2h, solve for h

A)h = V/2r2

B)h = V2πr2

C)h = V - 2πr2

D)h = V/2πr

2)Solve the equation for y: -8x + 4y = 20
A)y = 2x - 5

B)y = 2x + 5

C)y = 1/2x + 5

D)y = 1/2x + 20