Answer: 3(10^5) 
=3*10^5 
=3*(10*10*10*10*10) 
=300000
This is how you should do It, just when it is squared you should times the number like up here you times 10 times 10 5 times so if you see it you don't times it by 5 you do 10 times 10 times 10 times 10 times 10 like this 
You should get it now
Have a good day
Yours,
Nathaniel
Explanation: