Factorise 2a + 6 ? i literally forgot how to factorise

You need to find a factor  of 2a and 6 - what number divides into both of these?  Its 2. 
so Dividing 2 into  2a + 6 gives you the other factor in the parentheses:-

Answer is 2(a + 3)

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?