The scientific notation of the given, 35,000,000 is 3.5 x 10^7. The order of magnitude of a scientific notation is the exponent of its multiplier, 10. From the derived scientific notation above, the exponent of 10 is 7. Thus, the answer is letter D.
-149 divided by 2 is 74.5 and sense we want a 5 difference we divide 5 by 2 to get 2.5 the we take 74.5 and add 2.5 to get - 72 and take 74.5 and subtract 2.5 to get -77.