Day 71 – December 9

Algebra: Chapter 8 Review

TEST POSTPONED UNTIL TOMORROW. Make sure that your notes are up-to date!

Algebra: Chapter 9, Lesson 1, page 400.

Sets, Intersections and Unions

A set is a well-defined collection of objects called members or elements.

  • Roster notation LISTS the members of the set.
  • Set-Builder Notation gives a DESCRIPTION of how the set is built.

The intersection of 2 sets `A` and `B`, written `A ∩ B` is the set of all members that are COMMON to both sets. We say ” A intersection B”.

The union of 2 sets `A` and `B`, written `A ∪ B` is the set of all members that are in `A` or `B` or in both. If an intersection is EMPTY, we say the intersection is the empty set which is symbolized as `∅`.

All of these concepts are described here too with examples!

Two of tonight’s homework problems solved by MrE are here! Just click it!

¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦ ¤ ¦¦

Algebra 1a, Chapter 4, Lesson 5, page 187.

Using Inequalities

We learned key phrases for lesson 5 (word translation problems):

  • “Less than or equal to”, “is at most”, “no more than” — ≤
  • “No less than”, “at least”, “more than or equal to” — ≥
  • “Is less than” — <
  • “Is greater than” — >

We learned to read the problem, draw a picture or understand what is being asked of us before we start solving an equation or inequality.

Remember for 2 step inequalities, we do the same, again, as equalities and solve by:

  • Distributing when required
  • Combining like terms
  • Adding or subtracting terms to isolate variables and numbers (constants)
  • Multiplying or dividing to finish solving for the variable, remembering to reverse the sign of the inequality IF we multiply or divide by a NEGATIVE NUMBER.

Here are some keyword descriptions from purplemath.com to help us with word problems (ugh …)

Two of tonight’s homework problems solved by MrE are here! Just click it!

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