Question

Which of the following expressions represents a function?

{(1, 2), (4, –2), (8, 3), (9, –3)}
y2 = 16 − x2
2x2 + y2 = 5
x = 7

Answer 1

the 1st one has 4 points, and their coordinates, plot those
then for the last 3
pick a few random "x" to get a "y", and plot them as well

then run the "vertical line test" on the graphs of each
see which one passes

http://i1.ytimg.com/vi/-xvD-n4FOJQ/hqdefault.jpg <-- vertical line test

Answer 2

so it would be a @jdoe0001

Answer 3

if that's what your graphs show, then sure

Answer 4

@jdoe0001 a is correct?