First, you are going to want to get the terms to the same power of 10 in scientific notation. Realize that [tex]9.3 \cdot 10^7 = 9.3 \cdot 10^6 \cdot 10^1= 93 \cdot 10^6[/tex]. Essentially, we have converted the [tex]9.3 \cdot 10^7[/tex] to a term with [tex]10^6[/tex]. Now, we can subtract the values in each term that are not 10 as shown below:
[tex]93 \cdot 10^6 - 3.14 \cdot 10^6[/tex]
[tex](93 - 3.14) \cdot 10^6[/tex]
[tex]89.86 \cdot 10^6[/tex]
Remember that we have to turn it back to scientific notation once we are done!
[tex]89.86 \cdot 10^6 = 8.986 \cdot 10^7[/tex]
Our answer is the second choice, [tex]8.98 \cdot 10^7[/tex]. (This is the closest answer to [tex]8.986 \cdot 10^7[/tex].)
