Coeffecient of x in -7xyz2

What is the binomial expansion of (2x-3)^5

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

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