Question

Which set is a function?
A)
{(0,3), (3,0), (0,4), (4,0)}
B)
{(0,2), (2,0), (4,6), (6,4)}
C)
{(2,6), (3,6), (4,6), (2,0)}
D)
{(0,4), (0,9), (12,6), (-3,9)}

Answer 1

look at choice A

notice how we have the points (0,3) and (0,4)

So when x = 0, y is both 3 and 4 at the same time...but that's impossible because y can only equal one value at a time (for a certain x value)

So choice A can't be a function

Answer 2

f(x) = x2 + 3x - 7
For the function shown, what is the range of the function when the domain is {-3, 2, 5}?
A)
{-7, 33}
B)
{3, 11, 21}
C)
{-7, 3, 33}
D)
{-7, 11, 33}