If (x+3)+3(x-1)=20, what is the value of x

1(x + 3) + 3(x - 1) = 20
1(x) + 1(3) + 3(x) - 3(1) = 20
               x + 3 + 3x - 3 = 20
               x + 3x + 3 - 3 = 20
                                4x = 20
                                 4      4
                                  x = 5

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?