Which set of ordered pairs could NOT represent a function? a.) (1, 1), (2, 2), (5, 5), (7, 7), (13, 13)
b.) (1, 5), (2, 6), (3, 6), (4, 5), (5, 4)
c.) (2, 3), (3, 4), (2, 5), (5, 6), (2, 7)
d.) (3, 2), (2, 1), (4, 3), (5, 4), (6, 0)

Can someone explain to me how to do

Write the equations in logarithmic form 9^4=6,561

The dance committee of pine bluff middle school earns $72 from a bake sale and will earn $4 for each ticket they sell to the spring fling dance. the dance will cost $400 write an inequality to determine the number, t of tickets the committee could sell to have money left over after they pay for this year's dance. what is the solution set of the inequality?