ALGEBRA!!!!

Determine whether each relation represents a
function. For those that are functions, state the
domain and range.
a. {(1,4), (2,5), (3,6), (4,7))
b. {(1,4), (2,4), (3,5), (6,10))
c. {(-3,9), (-2,4), (0,0), (1,1), (-3,8)}