Question

l87n/987/8

Answer 1

a one to one function is a function such that f(a)=f(b) implies a=b.
So we know y=x^2 is not one to one
because -1 doesn't equal 1 but f(-1)=f(1)

Answer 2

or whatever
we can just think about the horizontal line test if that makes things easier for you

Answer 3

to me y=|x| is easiest to draw of the 4

do you think this passes the horizontal line test

Answer 4

draw infinitely many horizontal lines on your picture
if your function touches any horizontal line more than once then it is not 1 to 1
so if there is just one horizontal line that touches the function more than once then isn't 1 to 1
so y=|x| is one to one or not one to one?

Answer 5

@freckles ?