Free ACT Functions practice questionsEnhanced ACT, 2026 format
Function notation and graphs, arithmetic and geometric sequences, and trigonometry: right-triangle ratios, radians, periods, and the basic identities.
Answer each question, then read why the right answer is right and why the tempting one is wrong.
Question 1
Given f(x) = 2x^2 - 3 and g(x) = x + 4, what is the value of f(g(-1))?
Question 2
A population of bacteria doubles every 3 hours. If the population is 500 at noon, which expression gives the population t hours after noon?
Question 3
A 20-foot ladder leans against a vertical wall so that it makes an angle of 65° with the level ground. Which of the following is closest to the height, in feet, at which the top of the ladder touches the wall? (Note: sin 65° ≈ 0.906, cos 65° ≈ 0.423, tan 65° ≈ 2.145)
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