Answer:
8.4x10^5 is the first answer. 9.16 x 10^-6 is the second one.
Explanation:
Let me explain. To find scientific notation of a number, you have to make the number greater than 1 and less than 10. So for the first number, you would have to move a decimal place 5 times to the right to make 840,000 less than 10 and greater than 1. But, you still have to add the exponent. So the amount of numbers you move the decimal point to the left, that will be your exponent.
2nd. BUT, for the 2nd number, this number is not 1 or greater than 1 or less than 10. So you would have to move it to the right. If your moving a number to the right, remember the exponent will always be negative. So you would move it 6 times to the right.
I hope this made sense. If it didn't, don't worry! You'll get the hang of it.