a, 5 - 2 . x = 2
2 . x = 5 - 2
2 . x = 3
x = 3 : 2
x = 1,5
-> D = {emptyset}
2,
a, (44 . 52 . 60) : (11 . 13 . 15)
= (44 . 52 . 60)/(11 . 13 . 15)
= 4 . 4 . 4
= 4^3
= 64
b, (98 . 7676 - 9898 . 76) : (2001 . 2002 . 2003 . ... . 2010)
= (98 . 76 . 101 - 98 . 101 . 76) : (2001 . 2002 . 2003 . ... . 2010)
= 0 : (2001 . 2002 . 2003 . ... . 2010)
= 0
3,
a, A = 2010 . 2010 ; B = 2009 . 2011
2010 . 2010 = (2009 + 1) . 2010 = 2009 . 2010 + 2010
2009 . 2011 = 2009 . (2010 + 1) = 2009 . 2010 + 2019
Vì 2010 < 2019 nên 2009 . 2010 + 2010 < 2009 . 2011
=> A < B
b, A = 234234 . 233 ; B = 233233 . 234
234234 . 233 = 234 . 1001 . 233
233233 = 233 . 1001 . 234
Vì 234 . 1001 . 233 = 233 . 1001 . 234
=> A = B