Answer:
7.2 x

Explanation:
7.2 x

To write the number in scientific notation, you need to move the decimal from where it is at at the end of the number so that the number will be 1 or greater than 1, but less than 10.
7,200,000. If we do not see a decimal, it is at the end of the number. We moved the decimal between the 7 and 2. How many places did we move the decimal. It was at the end of the number and now it is between the 7 and the 2. We moved it 6 places. That tells us what the exponent will be.