What is the domain of this relation?



$\begin{array}{l}

(0,2) \\

(1,9) \\

(-9,6) \\

(-4,7)

\end{array}$


A\{1, 4, 9\}
B\{-9, -4, 0, 1\}
C\{-9, -4, 1\}
D\{0, 1, 4, 9\}

Verified Answer :

  • The domain of a relation is the set of all first coordinates (x-values) from the ordered pairs.
  • Extract the x-coordinates from the given relation \(\{(0,2), (1,9), (-9,6), (-4,7)\}\), which are \(\{0, 1, -9, -4\}\).
  • Order the set numerically to get \(\{-9, -4, 0, 1\}\).
  • The correct option is \(\boxed{b}\).

Explanation

  1. Understanding the Domain of a Relation

The domain of a relation consists of the set of all first coordinates, or \(x\)-values, from the given set of ordered pairs. The relation provided is a set of ordered pairs: \(\{(0,2), (1,9), (-9,6), (-4,7)\}\). To find the domain, we extract the first element from each of these pairs.

  1. Extracting the x-coordinates

From the given ordered pairs \((0,2)\), \((1,9)\), \((-9,6)\), and \((-4,7)\), the first elements are:

  • From \((0, 2)\), the x-value is \(0\).
  • From \((1, 9)\), the x-value is \(1\).
  • From \((-9, 6)\), the x-value is \(-9\).
  • From \((-4, 7)\), the x-value is \(-4\).

Collecting these values, we get the set \(\{0, 1, -9, -4\}\).

  1. Identifying the Correct Option

To write the set in a standard way, it is helpful to list the elements in ascending order. Arranging the numbers \(-9, -4, 0,\) and \(1\) from smallest to largest gives: \(\{-9, -4, 0, 1\}\). Comparing this result with the provided options:

A\(\{1, 4, 9\}\)
B\(\{-9, -4, 0, 1\}\)
C\(\{-9, -4, 1\}\)
D\(\{0, 1, 4, 9\}\)

The result matches option b.

Examples

In real life, identifying the domain is like listing all the unique items you have available to make a selection from. For example, if a store offers specific menu combinations, like (burger, \$10), (pizza, \$12), and (salad, \$8), the domain would be the set of food items {burger, pizza, salad}. Understanding how to isolate the input values from a set of data helps in organizing information for databases, scheduling, and resource management.