Day 78 – January 3

Algebra: Chapter 5, Lesson 4, page 217.

Scientific Notation

We can write numbers as the product of a power of 10 and a number greater than 1 but less than 10 (9.9999…. to be exact). Standard notation is the stuff that we are normally used to.

Examples: `4.58 × 10^4=45,800`
`(3.0 × 10^5)(4.1 × 10^(-3))=(3.0⋅4.1 ) * (10^5 × 10^(-3))=12.3 × 10^2=1.23 × 10^3`

`(2.5 × 10^(-7))/(5.0 × 10^6) = (2.5/5.0) * (10^(-7)/10^6) = 0.5 × 10^(-13) = 5.0 × 10^(-14)`

More scientific notation examples are here.

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

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Algebra 1a: Chapter 4, Lesson 3, page 180.

The Multiplication Property of Inequalities

The property states if `c` is POSITIVE

  • if `a < b`, then `ac < bc` and
  • if `a > b`, then `ac > bc`

Where `c` is NEGATIVE

  • if `a < b`, then `ac > bc` and
  • if `a > b`, then `ac < bc`

Following the EXACT same steps as equalities, we have learned to solve 1 step equations with inequalities. The ONLY difference is when multiplying or dividing by a NEGATIVE number, we must REVERSE the sign of the inequality for the final solution!! If we divide or multiply by a positive number, we leave the inequality sign alone.

Here are some examples from purplemath.com that have to do with inequalities with products and divisions.

Two of tonight’s homework problems are here for Chapter 4-3 as well!

 

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