Simplifying Algebraic Expressions

The properties of real numbers are very important in our study of Algebra. These properties can be applied in Algebra because a variable is simply a letter that represents a real number. The distributive property is one that we apply often when simplifying algebraic expressions. Given real numbers a, b, c:
a(b + c) = ab + ac
When multiplying an expression within parentheses you must multiply everything inside by the number or variable that you are distributing.

Introduction to the Distributive Property

Simplify.
When simplifying, we will often have to combine like terms after we distribute.  This step is consistent with the order of operations, multiplication before addition.


Combining Like Terms


Simplify.

Simplifying Algebraic Expressions

To combine like terms, the variable parts have to be exactly the same.  But before combining like terms, generally, we will first distribute if necessary.  When distributing negative numbers notice that the operations change.

Simplify.


Profit Word Problem: Profit is equal to revenues less cost of production.  If the revenue R can be represented by
and the cost C can be represented by
where x represents the number of units produced, find an equation that represents the profit.
Subtracting Variable Expressions: What is the difference between 3x − 4 and −2x + 5?
Video Examples on YouTube:
      
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Finding Linear Equations

Slope intercept form also allows us to easily find the equation of the line given the graph.  If you are given the slope and any point on the line you can find its equation by following the steps below:

Example: Find the equation of the line passing through (2, 3) with slope m = 1/2.

   Step 1: Use y = mx + b and find m.
   Step 2: Use the given point to find b.
   Step 3: Put it all together using y = mx + b.
Alternatively, you can use point-slope form to answer the same question.
Substitute (2, 3) and slope m = 1/2  into the formula as follows:
Either method is valid and the answer is the equation.

Find the equation of the given line.


Video Examples on YouTube: