So first, you want to combine the x's. To do this, count the x in (x+3) as 1. So the x's combined are equal to 3x. Now, combine the 3 and -1. This expression simplified is equal to [ (3x+2) ]
use the distributive property and yet rid of the parenthesis (or however you spell that) and get x+3×2x-1 then add like terms and get 3x+2. that's your answer. 3x+2