Question

I need help understanding functions.
Determine whether function is one-to-one and graph:
f(x)=-2x-7

Answer 1

my teacher solved like this, and said that, Yes it is 1-1. explain?

Answer 2

I guess I'm just having touble remembering how to solve a function

Answer 3

1-1 meand that wherever you cut through the graph of the function, you'll get only one solution.

Answer 4

For the above curve, you'll get two solutions when you cut through it.

Answer 5

*means

Answer 6

So the function of this curve is not 1-1.

Answer 7

where do the points (0,-7) and (-9,2) come from?

Answer 8

I get that -2 an -7 are the -9, but what about the rest?

Answer 9

I am not sure but according o the graph you drew, the points I see are (0,-7) and (2,-9).
The first one is correct beacuse when you replace 0 in the function i.e
f(x)=-2x-7
y=-2(0)-7
y=-7
So when x=0, y=-7.
There seems to be a mistake with your second set of points. Because if you replace x=2 in the function, you get
y=-2(2)-7
y=-4-7
y=-11 --> (2,-11).