how do i factor out the coefficient of the variable ex. 2b+8

Question

i dont understand this. . . 

Answer 1

2b + 8  =  2 (b + 4)

The coefficient of b (that is, 2) divides into 2b and also into 8, so it is a factor (a value that is multiplied by another value to produce a term in an expression)  --  get those definitions !!

Answer 2

2 is the coefficient of 2b

2b + 8

2(b) + 2(4)             2 is a common factor

2(b + 4)