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How do you find out which of these is a function?
A) x=(y^2)+2
B) {(6, -5),(6,2),(2,-1)}
C) {(-1, 6),(3,6),(-5,6)}
D) (3x^2)+(4y^2)-5=1
I have no idea
3 Answers
- Anonymous8 years agoFavorite Answer
Each function has domain and range. It must have a real solution also (depending on what class your taking). So the domain can't have the same range meaning the x input can't have two y outputs. Try graphing it, you'll see.
Source(s): Math is my life... LOL no but I'm a precalc student - 8 years ago
it is C. My teacher taught me the "birthday rule" Think of "x" as people, and "y" as dates. For example: The answer to B.
(6, -5) (6, 2) <--- Same person (6) with 2 different birthdays?!?!? Doesn't work.
BUT C:
(-1, 6) (3, 6) (-5, 6) <--- SAME birthdays, BUT DIFFERENT people. So it works!
- 8 years ago
THE ANSWER IS C(:
A function
•can't have exponents
•no X times Y
•and no x or y in the denominator
So you can cross out A and D, and x can't repeat, so you can cross out B(:
Source(s): 8th graders brain-.-