Question

All of the following points lie on the graph of
y = 2x(the x is an exponent)except _____.


(0, 0)
(1, 2)
(2, 4)
(3, 8)

Answer 1

Substitite x and y coordinates of every point for respectively x and y in the equation and see in which case it isn't equal.

Answer 2

Do you understand?

Answer 3

I'm new to this stuff so... no.

Answer 4

Oh, ok. An example: let's take a point (1,2). Its x-coordinate is 1 and its y-coordinate is 2. If it lies on our line, then these numbers must solve (so give 0=0 in the end) its equation.
Let's see:
2 = 2^1
2 = 2
0 = 0
Ok, so this point indeed lies on the line. Do the same stuff with other points, ok?

Answer 5

Alright.. Thank you~

Answer 6

To make myself sure - what answer did you get? :)

Answer 7

I'm trying to do the problem right now.. >^<

Answer 8

Oh, sorry for disturbing then.

Answer 9

Is it (3,8) ? >^<

Answer 10

Unfortunately no. Because then x=3 and y=8. Is it true that 8 = 2^3? It is, so it must lie on the line. Take a look at the point (0,0), though. What is 2^0?

Answer 11

*sighes* I think I need to hit the books. I don't understand this at all. I am absolutely terrible at math.

Answer 12

It must be a minor thing that's blocking you. Okay, so I'll show you how to do this at least. For point (0,0), we have x=0 and y=0. Let's substitute this into the equation of our line:
y = 2^x
0 = 2^0
But 2^0 = 1. (Perhaps you didn't know that?)
We get 0=1, but it is not true! Therefore this point doesn't lie on the line, because its coordinates doesn't satisfy the equation.