f(x) = x when 2 ≤ x < 5
So you can use this function if "x" is greater than or equal to 2 and less than 5
f(x) = 2x when 5 ≤ x < 10
You can use this function if "x" is greater than or equal to 5 and less than 10
f(6) This means that x is 6, so you can plug in 6 for "x" in the equation.
You use the second function because 6 is greater than 5 and less than 10
f(x) = 2x
f(6) = 2(6)
f(6) = 12 Your answer is B