SAT Math

Master the essential math concepts and problem-solving skills needed to excel on the SAT.

Basic Concepts

Working with Functions

Understanding Functions

Functions are like machines: you put something in (the input), the machine does its magic, and you get something out (the output).

A function can be written as \( f(x) \), where \( x \) is the input.

Evaluating Functions

If \( f(x) = 2x + 3 \), and you want to know \( f(4) \):

  1. Substitute 4 for \( x \): \( f(4) = 2(4) + 3 = 8 + 3 = 11 \).

Graphs and Tables

Functions can be shown as graphs or tables. Seeing patterns helps with predictions and understanding trends.

Real-Life Connections

  • Predicting your phone bill based on usage.
  • Figuring out how many points you need on a test to reach your target grade.

Common Function Types

  • Linear: \( f(x) = mx + b \)
  • Quadratic: \( f(x) = ax^2 + bx + c \)
  • Exponential: \( f(x) = a \cdot b^x \ )

Examples

  • If \( f(x) = x^2 \), then \( f(5) = 25 \).

  • A taxi fare: \( f(miles) = 2.50 + 1.75 \times miles \).

In a Nutshell

Functions connect inputs to outputs, showing how one thing depends on another.

Key Terms

Function
A rule that assigns exactly one output to each input.
Linear
A function whose graph is a straight line.