Respuesta :

you would have to subtract  that is what is being done you do the opposite of 8.5 which is to subtract  -8.5 on both sides  y equals 8.7

Answer:

the answer is that the number 8.5 is going to be subtracted.

Step-by-step explanation:

It says in the lesson when a number is going to b added it must be subtracted if the number is going to be subtracted it is going to be added.

so 17.2 - 8.5 = Y. There you go. Welcome.