How do i solve ×- 13 = 1

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

If g^-1(x) is the inverse of g (x) which statement must be true

Clarence wants to buy a new car. he finds an ad for a car that costs 27,200 dollars. suppose his local sales tax is 7%. -how much would he have to pay? -what is the cost of the car including tax? -if clarence has 29,864 saved, can he pay cash to buy the car?