During a football game, a team lost 9 yards on the first play, then gained 3 yards on each of the next 3 plays. Which integer represents the total number of yards at the end of the first four plays?
-3
0
Oo oo
9
18

Marco is studying a type of mold that grows at a fast rate. he created the function f(x) = 345(1.30)x to model the number of mold spores per week. what does the 1.30 represent? how many mold spores are there after 4 weeks? round your answer to the nearest whole number. 1.30 represents the number of mold spores marco had at the beginning of the study; 985 mold spores 1.30 represents the number of mold spores grown in a given week; 448 mold spores 1.30 represents the 30% rate of weekly growth; 345 mold spores 1.30 represents the 30% rate of weekly growth; 985 mold spores

How do you solve a question like this?

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?