# Math Help - factorise

1. ## factorise

hi this is my question:
i need to factorise this, 3x^2-7x?
for this question im not sure how i would answer it so could some help me please?!?
Thanks!

2. perhaps $x(3x-7)$

3. how would that work?
is it because you times what evers out side the bracket by what is in so x times 3x= 3x^2 and x times 7= 7x?

4. Originally Posted by andyboy179
is it because you times what evers out side the bracket by what is in so x times 3x= 3x^2 and x times 7= 7x?
Excactly

5. thanks! how would i factorise x^2-9??

6. x^2-9=x^2-3^2=(x+3)(x-3)

7. Originally Posted by andyboy179
thanks! how would i factorise x^2-9??
I cannot believe for one second that you do not have examples in your classnotes or textbook of the techniques required to answer the two questions in this thread.

Common factor.

Difference of two squares.

Review it.