Negative Numbers and Letters
In this chapter we’re going to look very broadly at how negative and positive numbers and letters work. There are some rules that you should know when working with negative and positive. These rules are shown below.
A positive number plus positive results in a positive.
A positive and a negative results in a negative.
A negative and s positive results in a negative.
A negative with a negative results in a positive.
Number line
Here we shall look at some examples of number lines.
Example
You can use the number line to prove the results above, also to help you when adding and subtracting. The following is known as the number line.
Suppose we had an equation that we wanted to solve such as 4x-8x-3x+6x=? We can use the number line above starting from 4 to solve this. We subtract 8 from 4 at start.
Then we subtract 3 starting from where we ended.
Next we add 6 as instructed in the equation. This is shown below.
…where we ended is the answer and that answer is -1 which means;
Multiplication of letters
We shall look at some examples of multiplying letters
Example
Using letters is very popular in algebra. It’s therefore important to understand how they work especially the notation of multiplications between letters. Below we shall look at some of the rules when working with multiplication and letters.
In algebra we use the simplified notations to represent what would otherwise be a long line of multiplication as shown above.
Difference of two squares
Difference of two squares is also often noted as D.O.T.S for short. It’s where you have one thing squared minus another thing squared. The general expression of the difference of two squares is shown below.
The above simply shows the factorisation of a2 – b2.
Example
Factorise x2 – 16.
If you have some factorisation skills this would be extremely easy. The result would be;
We simply square rooted each term in the expression and put it in the brackets in such a way that when the brackets are removed it will outcome x2 – 16.
this did not help me at all
I wanted to know how to minus numbers from letters