To find if one is a function, you must see if the pattern is the same. Domains (x) can not have two values I forget what the y value is called, but there can be the same y- value for multiple x - values
A. is not a function, because its ordered pairs are all over the place, and the value 4 in the x - value has two values assigned - 0 and 3, which makes it invalid.
B. may be a linear function. Its ordered pairs aren't jumping all over the place. Both the x and y go up one for one, so the function could be y = x + 3
C. isn't because the x - value 2 has two values. Again, that makes this invalid.
D. is invalid because there is two x - values for 2.
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