How do you write 8.69 × 10^-5 in standard notation?

Need with son's homework i will give 30 ! show work daniel's house is located b miles from his school. the swimming pool is 3 miles farther from his school. his dr. office is 4 miles less than twice the distance from home to daniel's school. a. write an expression that shows the distance from daniel's house to the swimming pool. b. write an expression that shows the distance from daniel's house to his dr's office c. if b=3, is the swimming pool or dr's office closer to daniel's house? how much closer