When multiplying terms in scientific notation, we multiply the numbers in front and add the exponents
(a* 10^b) (c* 10^d) = ac * 10^(b+d)
(9.1 × 10^9)(7.5 × 10^2) = (9.1*7.5) * 10^(9+2)
=68.25 * 10^11
But this is not proper scientific notation. We can only have 1 number in front of the decimal. We need to move the decimal 1 place to the right. That adds 1 to the exponent.
