Question

Which graph best represents the function f(x)=2x ?

Answer 1

B

Explanation:

The best - well, only way- is to check a few points.

Namely -1 (unless your eyesight is really poor!), 0, 1, 2, and 3.

`f(x) = 2^x\\f(-1) = 2^-^1 = \frac12\\f(0) =2^0 =1\\f(1)= 2^1=2\\f(2)=2^2=4\\f(3)=2^3= 8`

Now you can mark all these points in each graph (well, you could if they were on paper and not on a screen) and see which one of the lines passes through all of them. Spoiler alert, it's the B graph.

A represents
`2(2^x) = 2^(x+1)`, B is the one you want, C is
`\frac{2^x}2 = 2^(x-1)` and D looks like
`4^x = 2^2^x`