We are asked to sum the two trinomials

. We can start by using the distributive property to remove the parenthesis, giving us

. Next, when we combine like terms, we get

. Hope this helped!
Answer:
2.13 X 104 square acres
Step-by-step explanation:
Divide 6.4 acres by 3 miles = factor of 2.13
Therefore the answer must be 2.13 X 104 square acres