Do what it says.
F = (9*30)/5 +32 . . . . . replace the variable C with the value 30
F = 270/5 +32 . . . . . . . order of operations says do multiplication and division in the order in which they appear. We have multiplied 9*30
F = 54 +32 . . . . . . . . . . division appears next. We have divided 270 by 5
F = 86 . . . . . . . . . . . . . . after multiplications and divisions are done, we add in the order of appearance. There is only one addition to perform.
F = 86 . . . . . . . . we suppose only the numerical value 86 should be entered