According to the meaning: A 2+(A+2) 2 =100.
Agenda solution: 2a 2+4a+4 =100.
a^2 + 2a + 2 = 50。
a^2 + 2a - 48 = 0。
A =[-2+ radical sign (4+ 192)]/2
=- 1+ root sign (49)
= - 1 + 7
= 6.
A: These three serial numbers are: 6, 7 and 8.