Answer:
1)50400000
2)980000
3)-5680000
Step-by-step explanation:
1)4.7*10^7=4.7*10000000=47000000+(3.4*10^6=3.4*1000000)=3400000+47000000=50400000
2)9*10^5=100000*9=900000+(8*10^4=10000*8)=900000+80000=980000
3)2.8*10^-5=-280000+(5.4*10^-6)=-5400000+(-280000)=-5680000
