To evaluate the value of the expression 6(n+4) with n = 3, we just have to replace 3 for n into the expression, like this:
6(n + 4)
6(3 + 4)
Now, perform the sum inside the parenthesis, to get:
6(7)
Now, multiply 6 by 7:
6*7=42
Then, the answer is 42