Solving for a Variable on One Side of the Equal Sign
When you have an equation with a variable in it and you want to find out what number that variable stands for, you need to solve the equation for that variable. First, you simplify each side of the equal sign in the same way that you simplify expressions; next, you get the variable on one side of the equal sign and all the numbers on the other side. You can do this using inverse operations, which are operations that undo one another. Addition and subtraction are inverse operations. Multiplication and division are also inverse operations. When you have an equal sign, you must do the same operation to both sides so that the equation stays balanced. If you have x + 2 = 5, you subtract 2 from the x to get x all by itself. Remember also to subtract 2 from the 5 on the other side of the equal sign to keep the balance.
x + 2 = 5
-2 -2
x = 3 Check: 3 + 2 = 5
Here is a good tutorial on solving for a variable: http://library.thinkquest.org/20991/alg2/eq.html
x + 2 = 5
-2 -2
x = 3 Check: 3 + 2 = 5
Here is a good tutorial on solving for a variable: http://library.thinkquest.org/20991/alg2/eq.html
_If the video above is not working, you need to download the Adobe Flash player.
Next is a good video on what to do if your variable is part of a fraction.
Next is a good video on what to do if your variable is part of a fraction.
If you are confused about where to begin, ask yourself:
- Are all like terms on either side of the equal sign combined?
- Did you move all constants to one side of the equal sign and all variables to the other using addition and subtraction?
- Before you multiply or divide a variable by a constant, is the term with the variable all by itself on one side of the equal sign?
When you get an answer, don't forget to check it.
PRACTICE
Try this applet: http://waldomaths.com/Equation2NL.jsp.
ASSESS
Test yourself with this game: http://www.vectorkids.com/vkvariable.htm. How many did you get in a minute? Post your score in the game forum below.
Now let's move on to Solving for a Variable on Both Sides of the Equal Sign.
_Copyright © Lisa Sheridan, 2011. All Rights Reserved.
No original material may be copied from this website without
explicit permission from the author.
No original material may be copied from this website without
explicit permission from the author.