Sunday, October 26, 2008

algebraic equations

 Sorry last post was a mistake. Today's topic is algebraic equations. The vocabulary for today is the words variable and equation. A variable is a letter that is used to represent an unkonwn number.  An equation is a number sentence that shows that two expresions are equivalent. There are three steps to solving algebraic equations. Step 1  -Ask yourself what is being done to my variable. Step 2 - do the inverse operation of what is being done to the variable. Here is an example the inverse operation of addition is subtraction and the inverse operation of multiplication is division. It is the opposite if division or subtraction is being done. Example of doing this is here.





                                                                                                6=x-9
                               Subtraction is being done to the variable so we do addition. Like this...
                                                                                                
                                                                                              
                               
                                 6+9=15 and since 9 is being subtracted adding nine cancels the nine out. 

Since nine is canceled out all we have left is 15=x which is true we found the variable x=15. All step three is write out the variable equals whatever the answer is. That is it that is how you solve it.
                                                                        That looks likes this
                                                                                       6=x-9
                                                                                     +9=x-9 
                                                                                         15=x

                                                    Now I will teach you how to check it 
First write the equation. Next plug in your answer. Then, add it up and write your answer equals the answer to the equation. Finally write the variable = you answer and that is how you check it Example 
                                                                                    6=x-9
                                                                                    6=15 -9
                                                                                      15=15
                                                                                       x=15
You could use this in life when you fill up your gas tank.If you have 20 dollars and gas is 3.50 a gallon and you want to know how many gallons you can buy you use algebra to find the answer.

1 comment:

oroarkclass said...

Very good job with your definitions and explanation. The 2nd line of your example is incorrect. It should simply be +9 +9. Let me know if this doesn't make sense.