My substitute teacher gaves us a worksheet that asks us to do problems we've never had before. How do I do unions and intersections on a number line using inequalities? Is there a formula for this?

Example: A intersects C
A={x|x>-3}
C={x|x greater than or equal to 0}

Example 2: A union C
A and C equal the same as above.

search for "algebra of sets" and you will get webpages like this:

http://www.bookrags.com/research/algebra-of-sets-wom/

To find the union and intersection of sets represented by inequalities on a number line, you need to analyze the conditions for each set and then combine or find the common elements accordingly. Let's break down each example:

Example 1: A intersects C
A={x|x>-3}
C={x|x greater than or equal to 0}

To find the intersection of A and C, you are looking for the elements that satisfy both conditions. In other words, you are looking for the values that are greater than -3 and greater than or equal to 0.

To represent this using inequalities, you can set up the condition:
x > -3 AND x ≥ 0

To combine these inequalities, you can use the AND operator (∩). The intersection represents the values that satisfy both inequalities. In this case, the common elements are the values that are greater than 0 since that is the more restrictive condition.

So, the intersection (A ∩ C) = {x|x ≥ 0}.

Example 2: A union C
A and C have the same representation as in example 1.

To find the union of A and C, you are looking for all the elements that satisfy either one or both conditions. In other words, you are looking for values that are either greater than -3 or greater than or equal to 0.

To represent this using inequalities, you can set up the condition:
x > -3 OR x ≥ 0

To combine these inequalities, you can use the OR operator (U). The union represents all the values that satisfy either or both inequalities. In this case, any value greater than -3 or greater than or equal to 0 satisfies the conditions.

So, the union (A U C) = {x|x > -3}.

There is not a specific formula for finding unions and intersections on a number line using inequalities, but the key is to analyze the conditions of each set and then combine or find the common elements based on these conditions.