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## Algebra basics

### Course: Algebra basics>Unit 2

Lesson 1: Introduction to variables

# Why aren't we using the multiplication sign?

Great question. In algebra, we do indeed avoid using the multiplication sign. We'll explain it for you here. Created by Sal Khan.

## Want to join the conversation?

• Would my teacher take points off, if I don't use ˑ ?
• He shouldn't, and he probably won't, since x is still defined as the multiplication sign. If you are really careful and never confuse the multiplication sign x with the variable x, and it looks pretty clear to everyone else what you mean as you do math, there is no reason why you should lose points. Having said that, it really is easier to use . instead of x to represent multiplication, specially as the math you start to learn gets more and more complicated and the use of the variable x becomes more and more commom.
• at , why do mathematicians use "X" as a variable more often that most?
• x is actually the latin replacement for the arabic word that means "unknown" or "something." Here's a short video about it on Tedtalks: http://www.youtube.com/watch?v=YX_OxBfsvbk

Hope you foound this interesting :)
• What is preferred the dot or the x
• Once you get to Algebra, the x should no longer be used for multiplicaition, it is reserved for a variable. So the dot is now preferred, or use parentheses or an asterisk (*).
• Why do most people use x instead of other letters like p or s or even q?
• It's just a common variable to use. Many people use p, s, q, and every other letter (you'll even see Greek ones in geometry!).
• Why couldn't you just use a different symbol than x?
• You can use any letter or symbols to represent your number.
• At Sal says we can use a dot for a multiplication sign instead of an x. Why do mathematicians use a dot, and not some other sign?
• If you're asking why we use the dot specifically, it probably just arose because of its simplicity. We multiply things a lot in math, and mathematicians like to be efficient when they write. The dot (it's actually called an "interpunct" to be more specific) is so simple and short to write, that's probably why we use it instead of another symbol.
• is this correct way to solve 7+4b b=3

7+4b
= 4*3
=12+7
=19

is there another way I can solve this problem
• yep,that's the way I do the equation. But I do that more explained.Otherwise I can't understand the question.
7+4b,b=3
=7+4*(3)
=7+12
=19
only a little bit explained.
• Why does ( ) (Multiplying) Come before + & - (plus and minus)?
• Multiplication is repeated addition. If you have 2+4*2, that is equivalent to 2+(2+2+2+2). Hopefully this will help some.