Algebraic notation
In a nutshell
Algebra uses letters called 'variables' to represent unknown quantities. The basic rules for algebraic notation help write terms in a concise way. These terms can then be used in expressions, formulae or equations.
Example 1
The letter 'a' could represent an apple. Two apples could be described by 2a.
Basic rules
Adding equal variables
Add the numbers and copy the variable. If there is no number with the variable, it means 1. For example, x means 1x
Example
x+x=2x
Subtracting equal variables
Subtract the numbers and copy the variable.
Example
7x−5x=2x
Multiplying same variables
Multiplying the same variables changes the power. When multiplying, add the powers. If there is no number with the variable, it means 1.
Example
x×x=x2
Multiplying different variables
Write the letters without the multiplication sign. Multiplying different variables will not change their powers.
Example
x×y=xy
Adding/subtracting different variables
These cannot be added or subtracted so they will remain the same.
Example
a+b=a+b
Formulae
Formulae help find quantities.
Examples
Calculate the force (F) on an object from its mass (m) and acceleration (a).
- P=2(l+w)
Calculate the perimeter (P) of a rectangle from its length (l) and width (w).
- A=21bh
Calculate the area (A) of a triangle from its base (b) and its height (h).
Equations
An equation is formed when two expressions equal each other.
Examples
2x=5 |
|
x2−2x−8=0 |