Expanding brackets may be considered as multiplying out the brackets, removing the brackets or the reverse of factorising.
Check factorising again here
When you see this situation, 2 (x + 3 )
it just means multiply everything inside the bracket by 2.
So this situation is (2 times x) added to (2 times 3) which will give 2 x + 6
So, number next to bracket in this situation means multiply.
Watch out for the negatives on the outside of a bracket as all the signs inside the bracket will change. Remember to multiply by the number as well as change the sign!