factorise fully- 8y + 4y2

First of all you need to separate the two numbers 

you have 8Y

and 4y2

then ask yourself what you can divide both these 2 numbers with? so 4 can be divided by 4 and 8 can be divided by 4. so we can divide both equations by 4. 

Both equations also contain a Y. so we can divide both equations by Y. 

Whatever we divide these questions by we have to put outside the bracket. and whats left of the equation goes in the bracket. 

so we end up with 

4Y (2+y) 

the key to these types of questions is that you can expand out the bracket to see if you get the original question. this is a great way to test your answer!