The expression for g(x) is wrong, you skipped some signs and, apparentely, some parentheses. The rigtht expression for g(x) should be g(x) = 3(x+1) + 4. Note that g(x) = 3(x+1) + 4 it is the same that f(x+1) + 4. When you add a number to the argument, the graph of function is shifted that number of units to the left; and when you add a number to the function the graph shifts that number of units up. Therefore, the steps that will translate f(x) = 3x to g(x) = 3(x+1) + 4 is shift f(x) one unit to the left and four units up.
For the answer to the question on which steps will translate f(x) = 3x to g(x) = 3x + 1 + 4? The answer to this question is
f(x) = 3x one unit to the left and four units up
