The approximate total surface area of Earth is 5.1 x 108 km2. All the salt water on Earth has an approximate surface area of 352,000,000 km2.

All the freshwater on Earth has an approximate surface area of 9 x 106 km2 .
10
How much of Earth’s surface is covered by water, including both salt and fresh
water? Write your answer in scientific notation.

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14