Which of the following is an even function?

f (x) = |X|

f (x) = x - 1

f (x) = - 3%

F (x) = 2x

It's the first one.

Step-by-step explanation:

One test to see if a function is even is to check f (x) and f (-x). If they are equal then the function is even.

f (x) = |x|:

If x = x then f (x) = x, if x = - x then f (-x) = x, so this is an even function.

f (x) = |x|

Step-by-step explanation:

f (x) = x - 1 is a linear graph (remember y=mx+b)

So this line has a slope of 1, but just starts at y=-1

The f (x) = 2x is also linear

f (x) = |x| is a straight line, but one that never crosses below the x axis, because x is always a positive number (hence the |absolute| brackets). Therefor it makes a kind of upside down pyramid shaped graph that is a function.