a.=Sum(3,4,4,2,9,7) =29
b. =8000000*3 =24000000
=5.000.000*4 =20000000
=9.000.000*4 =36000000
=6.000.000*2 =12000000
=1.100.000*9 =9900000
=4.000.000*7 =28000000
c. =Sum(24000000,20000000,36000000,12000000,9900000,28000000)
=129900000
Chúc bạn học tốt.