How does factorising work?

Answer 1

Here is an example of factorising:

3ab+9b

The answer would be: 3b(a+3)

First, in 3ab+9b, you have to find LIKE TERMS. Like Terms are numbers, letters, etc. that are present in both the 'sides' (3ab is one side, 9b is the other). b is present in both. Now, you may be wondering about the 3 in the answer - this one: 3b(a+3). This 3 is here because it is the highest common factor for both 3 and 9 in (3ab+9b). In other words, three goes into both 9 and 3.

9 divided by 3 = 3 (this part - 3b(a+3) )

3 divided by 3 = 1 (this part - 3b(a+3) )

You don't need to put 1a, just a, because they are the same.

I hope you understood this. If not, get your teacher or a friend to explain it :)

Meanwhile, test yourself with these:

4ab+3a

7b+28ab

6ab2 + 7a2 b (this one's harder!)