Answer:
7. Cierto
8. Cierto (Yo creo)
9. Falso
10.Cierto
11.Cierto
12. Falso
Explanation:
9
n + n2 = 9 (n + 1)
9 + 92 = 9 (9+1) (of course, that '92' means '9 squared')
9 + 81 = 9 (10)
90 = 90
