Algebra I & II

So I’m sure you’ve heard the word variable before. Let’s find out what that is
What is a variable?
• For the first time ever, you can throw letters, globs, ducks, whatever you WANT into a math equation. A variable is nothing more than a placeholder. Even “😎” can be a variable!
• For example, we can define a variable x = 5. Now, we can say that Ethan x donuts. Guess how many donuts I have? I have 5 because we know x = 5.
• Now that we know what x is, we can do all kinds of stuff! Say that Zak has x+3 donuts. If we didn’t know what x was, this would make no sense; but, luckily, we do!
• This is as simple as 5+3, seriously!
• All we do is change x to 5 (since we know that’s what it stands for), giving us 5+3 and a total of 8 donuts for Zak.
x will not always be 5.
• For now, problems will tell you what x is, so just do the same thing as we did before.
• Now let's say that I have x nickels in my back pocket. I have twenty nickels in my back pocket. This means now, in this context, x = 20.
Your variable will not always be x.
• As we mentioned earlier, a variable can be anything.
• While this is technically true, most of the variables you will see will either be called x or y.
• It doesn’t matter what the variable is called, you still just change the variable into the number you know it equals.
Remember, a variable is just a number, so you can do all the normal operations on variables too!!
• If a = 9:
• a + 1 = 10
• a - 4 = 5
• 3 * a = 27
• a / 3 = 3
• a2 = 81
• √a = 3

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