Answer:
(5*10^3)*(9*10^7)=4.5*10^11
Step-by-step explanation:
5*10^3=5*1000=5000
9*10^7=9*10000000=90000000
5000*90000000=5*1000*9*10000000=5*9*10000000000=45*10000000000=450000000000, or 45 with 10 0's, or 10^10
45*10^10 is not simplified, as we need a number less then 10, so we divide 10 from 45, and add 1 to the exponent, getting 4.5*10^11
