Substitution, SUVAT

Use the correct equation below to work
out the terms required:

v=u + at, or v² = u² + 2as

a) u = 6ms ¹, a = 3ms2, v = 30ms ¹, find t.

b) a = 0.5ms², v = 10.5ms¹, t = 5s, find u.

c) u = 2ms ¹, v = 6ms¹, a = 0.5ms², find s.