1.5a-4.5= what is the answer to this question i don't get it

Hello. Because there are no like terms it just stays as 1.5a-4.5. Now it it told you to evaluate it when the variable a=(that number) then you would plug in that number for what the variable “a”. For example if it said, “Solve 1.5a-4.5 when the variable a equals 2” then you would still keep the equation as is but then multiply 1.5 by 2 which would be 3 the subtract by 4.5 to get 1.5 as your answer. Again I don’t know what it wants you to evaluate but if it told you to evaluate a number that would be the steps to take. Hope this helps a little bit!