Question 1

Can you use a ! for a variable?

Accepted Answer

Yes, you could but you might confuse it for a factorial.

Question 2

Where did they come up with the name variable?

Accepted Answer

If something varies, it changes from time to time. A variable is so named because it is capable of changing, as opposed to a numerical value, which must remain constant. Let me explain.

x could be anything. 1, 5, 273, 50 trillion--anything. Thus, it can vary in its actual value. This potential variability gives it the name variable. In contrast, the number 5 cannot change its value. It always will be 5. If it held a value of something other than 5, it simply wouldn't be 5. In this way, its value is constant. Hence, it is named a constant.

Question 3

How do you graph functions?

Accepted Answer

you need the table of points or the coordinates themselves. make the x and y axes on a piece of graph paper. You need an equation to plug in numbers for x and y variables too

Question 4

I know that x and y are the most common variables, but are you allowed to use other variables to?  Like O? 
Wondering,
  Allie

Accepted Answer

Yes. At 0:11, Sal uses "Tips" as the variable. At 2:20, he uses T to represent time.

Question 5

So, the only reason we use lowercase letters for variables is to keep things simple? So that means we can still use words, but letters is easier, right?

Accepted Answer

Letters are just shorter representations of objects. If we have 10 apples, it would be easier to write 10x, where x is being used to represent apples. It is much easier to use letters to represent variables rather than to write apples or whatever variable is being used.

Question 6

and what is tips
what is a variable
 why do we use them
 who created them

Accepted Answer

In this case,  tips are the sum of money given to someone as a reward for a service. For exemple: give a tip for a good waiter.
Now, a variable can be anything, it depends of the statement. In Math, when you make a statement, then it can be false or true. But, if you put a variable in a statement, so the proposition can be false and true either for different values. Therefore, a variable works how a question. For exemple:
x + 2 = 4 .  I have a statement and x is a variable because it can be any real number, but in truth it is a question: what numbers i can put in place the x and the results will be true? The answer how you know is 2. More one:  y - 5 = 2 + x. Now, you have 2 variables and several responses. Thats why we use them:  to work when we dont know the answer yet. In a function, for exemple, we have two variables: one is independent and other is dependent for the first one which means that when you change intentionally the independent then the dependent changes too. The speed is a exemple: if you have a constant speed, then  the distance is the dependent variable and the time is the independent variable. How much more time pass,  the distance you traveled increase in a same speed.
François Viète introduced at the end of 16th century the idea of representing known and unknown numbers by letters, nowadays called variables, and of computing with them as if they were numbers, in order to obtain, at the end, the result by a simple replacement. François Viète's convention was to use consonants for known values and vowels for unknowns.
In 1637, René Descartes "invented the convention of representing unknowns in equations by x, y, and z, and knowns by a, b, and c". Contrarily to Viète's convention, Descartes' is still commonly in use. I hope to have could help you. Good luck!

Question 7

Are variables hard and do they get harder in every grade you go in?

Accepted Answer

Variables are hard at first. Variables themselves get easier to use the more you use them, as with any concept. Math classes tend to get harder because they will expect you to use more variables in different ways. Yet the harder the math you do, the easier it becomes to use variables, and other ideas, to solve problems in your life. For example, what score do you need on your next test to get an A? This is a question that is much easier to answer using variables than without them.

Question 8

are variables used in things that are not math? if yes, then what?

Accepted Answer

Yes, the definition of a variable is anything that can change in a plan, for example weather can change so it can be counted as a variable in some cases.

Question 9

Why are x and y the most common variables?

Accepted Answer

I know why ‘y’ is chosen most frequently. I was surprised. You know when you ask someone for a reason why they can’t do something or just understand a concept better we ask ‘why’ therefor coming in as ‘y’

Question 10

can variables be anything else but x?

Accepted Answer

Yes, any letter could be used as a variable, though "x" is the most commonly used.  There are some letters that people stay away from because they look too much like numbers, for example: lower case L look like one (1); the letter O looks like zero (0).

Course: Algebra 1 > Unit 1

What is a variable?

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