For this case we must add the following expressions:
[tex]4.9 * 10 ^ 2\\6.8 * 10 ^ 3[/tex]
Rewriting we have:
[tex]4.9 * 10 ^ 2 = 490\\6.8 * 10 ^ 3 = 6800[/tex]
Adding we have:
[tex]490 + 6800 = 7290[/tex]
Answer:
7290 equivalent to [tex]7.29 * 10 ^ 3[/tex]