Answer:
?=7
Step-by-step explanation:
Here is a cool trick that I believe only works with 9.
Add the numbers, 3+9+9+8+x= divisible by 9.
3+9+9+7+8 is 36 which is the only number divisible by 9.
9 X 9 X 20 X 20
Pido perdón para mí español, pero creo que este es la ecuación.
