Question

Which function matches the mapping shown?

A)
f(x) = x2
B)
f(x) = 2x
C)
f(x) = x + 2
D)
f(x) = 2x + 2

Answer 1

looks like the squaring function

Answer 2

In this case, you just plug in each one to see if it works. Discrete stuff is nice like that.

A) f(x) = x^2
(-1)^2 = 1 yes!
0^2 = 0 yes!
1^1 = 1 yes!
2^4 = 4 yes!

B) f(x) = 2x
2(-1) = -2\[\neq\]1 no

C) f(x) = x+2
(-1)+2 = 1 yes!
0+2 = 2 \[\neq\]0 no

D) f(x) = 2x+2
2(-1)+2 = 0 \[\neq\] 1 no

So the answer is A. It wasn't really necessary to go through the others after figuring that out, but you see how it works.