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How do you write a linear equation as a linear function?

Published in Linear Functions 2 mins read

A linear equation can be written as a linear function by expressing it in function notation.

Understanding Linear Equations and Functions

A linear equation typically represents a relationship between two variables, often denoted as x and y. The most common form is y = mx + b, where:

  • m represents the slope of the line.
  • b represents the y-intercept (the point where the line crosses the y-axis).

A linear function is simply a way of expressing the same relationship using function notation. Instead of y, we use f(x), which reads as "f of x".

Converting a Linear Equation to a Linear Function

The key is to replace y with f(x) in the linear equation. According to the reference, "Another way to write y = mx + b is f(x) = mx + b. It means that there is a function of x which is in the form f(x) = mx + b. f(x) is the same as the y-value at point x."

Steps:

  1. Start with the linear equation: y = mx + b
  2. Replace y with f(x): f(x) = mx + b

Example

Let's say we have the linear equation:

  • y = 2x + 3

To write this as a linear function, we simply replace y with f(x):

  • f(x) = 2x + 3

This function, f(x) = 2x + 3, now represents the same linear relationship as the original equation. It tells us that for any value of x, we can find the corresponding y-value (or f(x) value) by multiplying x by 2 and adding 3.

Benefits of Function Notation

Using function notation, f(x), provides a clearer way to:

  • Indicate that y is a function of x.
  • Evaluate the function for specific values of x. For example, f(2) means we substitute x = 2 into the function.

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