Tell whether a FUNCTION if the following represents a function and NOT FUNCTION if not : f = {(1, 2), (2, 2),(3, 5), (4,5)}.

Tell whether a FUNCTION if the following represents a function and NOT FUNCTION if not: g = {(1, 3), (1, 4), (2, 5), (2,6), (3, 7)}  

Tell whether a FUNCTION if the following represents a function and NOT FUNCTION if not: H = {(1, 3), (2, 4), (3, 5), (3,6), (4, 7)}  

Find the value of z if the given equation is 4z-8y+4=0 if y=5.

Find the value of x if the given equation is x=4y-5 if y=3.