Question

which of these equations represent functions?
A. y=x^2
B.y^2=x^2
C.x^2-y^2=1
D. y=3x

Answer 1

can someone help

Answer 2

so which ones do you suspect are the likely functions?

Answer 3

d and a

Answer 4

yes

Answer 5

well, B and C are 2 hyperbolas, so you're right, they'd not pass the vertical line test
so let's check A

if x = 2, y = 4
if x = -2, y = 4

in a function each coordinate will have a corresponding value on the other coordinate
for every "x" they'd be a "y"

but you can't have repeats

as you can see above, x = 2 and -2, have the same y-coordinate of 4
thus is not a function

that'd leave you with D

Answer 6

ok but a does pass

Answer 7

yes it does pass the vertical line test
which is why I was thinking.... it's a function

Answer 8

maybe I'm confusing one-to-one's ..... yes, A is a parabola
and will pass the vertical line test

Answer 9

so A and D then, my bad :(