Functional horizontal line

Question

A function f is one-to-one if different inputs produce  ---Select--- negative different the same positive outputs. You can tell from the graph that a function is one-to-one by using the  ---Select--- Vertical Line Inverse Function Horizontal Line Curved Line Test.

Answer 1

one to one means for each x coordinate there is only one y coordinate

x is the input, y is the output

f is 1 to 1 if different inputs produce different outputs

from the graph you can tell if a function is 1 to 1 by using the vertical and and horizontal line test

if either line cuts the graph more than once, it's not a 1 to 1 function

vertical line test tells whether it's a function

horizontal line tests tells whether it's a 1 to 1 function

take a quadratic function y=x^2

it's function because it passes the vertical line test. Any vertical line cuts the graph only once

It's not 1 to 1 though, because it fails the horizontal line test. Horizontal lines with y>0 will cut the graph twice.

or try x=y^2

it fails the vertical line test, it's not a function

but it passes the horizontal line test, still it's not 1 to 1 but for every y value there is only 1 x value

for every x value though, there are 2 y values

It's not a function, so it's not a 1 to 1 function either.