33 + 45 + 7 = 85.
You seem to be unaware of the fact that you could have obtained the answer much more easily and quickly by using the calculator that comes as part of your computer.
17a + 21a + 45 = 38a+ 45
They are two terms of an expression
-45
There is no equation in the question, only an expression. An expression cannot have a solution.
-39 + 6 = -33
It is an algebraic expression.
45
45 is 136.36% of 33.
5/x4
No.
It is: (g-5)(g-9)
12/45 = 4/15