SAT Function Notation Practice
Function notation is just organized substitution. Read f(4) as 'the output when the input is 4,' then replace the input variable carefully.
What this page covers
Skill-focused practice with answers and explanations.
Free practice questions
Try these first, then use the app to build a full adaptive set.
If f(x) = 2x^2 - 3, what is f(4)?
Replace x with 4: f(4) = 2(4^2) - 3 = 2(16) - 3 = 29.
If g(t) = 5t + 12 and g(t) = 37, what is the value of t?
Set 5t + 12 equal to 37. Then 5t = 25, so t = 5.
If h(x) = x^2 + 4x, which expression is equivalent to h(x + 1)?
Replace every x with x + 1: h(x + 1) = (x + 1)^2 + 4(x + 1) = x^2 + 2x + 1 + 4x + 4 = x^2 + 6x + 5.
How to practice this topic
A few rules that make review sessions more useful.
- Circle the input. In f(a + 2), the whole expression a + 2 replaces x.
- When the output is given, set the function expression equal to that output.
- Use parentheses when substituting an expression into a function.
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