So, the answer is option K.įunctions can also be used to represent real-world applications. Let’s look at where \(x=5a\):Īt \(x=5a\), we have that the function value is \(8b\). Since the data is graphical, our inputs are \(x\) values and our outputs are \(y\) values. To find \(f(5a)\), we need to determine which output is associated with the input \(5a\). This time, the information is displayed graphically, rather than algebraically. Let’s take a look at another problem regarding inputs and outputs. This means that anywhere we see an \(x\), we replace it with a 3. Let’s plug in our input into our function to determine the output. We are given a function and an input, and are asked to find the output. The following questions are taken from the ACT’s official practice tests. Now that we have defined what a function is, let’s take a look at some practical applications. As a result, this fails the condition that must be met in order for something to be considered a function. At \(x=2\), the function actually has two outputs: 3 and -3. This is because it does not pass the Vertical Line Test. On the other hand, \(g(x)\) is not a function. This means that each input has been assigned at most one output, so we have a function. That is, at any point on the graph, if you drew a vertical line (represented in red), you would only intersect the graph precisely once. In this case, \(f(x)\) is a function since it passes the Vertical Line Test. This is also known as the Vertical Line Test: In fact, for every input, there can only be one output. However, this isn’t as simple as it looks. The most basic definition of a function is that it takes in a value and produces a result. About 12–15% (or 7–9 questions) of the test involves functions, so you’ll definitely need a comprehensive understanding of functions to do well.įunctions on the ACT + Practice Questions Questions involving functions on the ACT Math Test fall under the category Preparing for Higher Mathematics. The questions fall into the following categories: These questions are designed to test your knowledge of various mathematical concepts. The ACT Math Test consists of 60 questions, to be answered in 60 minutes. So, make sure you brush up on your function knowledge before taking the ACT Math Test! In this post, we’ll go over some of the important concepts you’ll need to know, as well as official practice questions that will help you assess your understanding. Whether you’re being tested directly on function knowledge or not, the majority of questions cover a fundamental understanding of functions. On the ACT Math Test, functions are unavoidable. How Will My ACT Score Impact My College Chances?.Functions on the ACT + Practice Questions.