Inactive Tutor answered 02/14/13
Remember the rules for order of operations:
Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction (PEMDAS)
There aren't any Parentheses or Exponents,, so the next step is Multiplication and Division.
5 times 10 is 50, so the new equation is 50 + -18 = n + 55
Next is Addition/Subtraction positive 50 added to a negative 18 is positive 32, so we now have
32 = n+ 55. We want n alone, so we subtract 55 from both sides to get
32-55 = n + 55 - 55. Finishing up the Math, n = 32-55 = -23