a)1.2+1.3+1.4+1.5=2+3+4+5=14
b)1.2+1.3+1.4=2+3+4=9
tk nha+kb nx!
1 . 2 + 1 . 3 + 1 . 4 + 1 . 5
= 1 . ( 2 + 3 + 4 + 5 )
= 1 . 14
= 14
1 . 2 + 1 . 3 + 1 .4
= 1 . ( 2 + 3 + 4)
= 1 . 9
= 9
kb nha
a, 1.2 + 1.3 + 1.4 + 1.5 = 2+3+4+5 = 14
b, 1.2+1.3+1.4= 2+3+4= 9
1.2+1.3+1.4+1.5=2+3+4+5=14
1.2+1.3+1.4=2+3+4=9