Isolate the n.
Do the opposite of PEMDAS (Parenthesis, Exponents (& roots), Multiplication, Division, Addition, Subtraction)
Note the equal sign. What you do to one side, you do to the other.
First subtract 5 from both sides
n/3 + 5 (-5) = 7 (-5)
n/3 = 7 - 5
n/3 = 2
Next, to isolate the n, multiply 3 to both sides
n/3(3) = 2(3)
n = 2(3)
n = 6
n = 6 is your answer
hope this helps