0.5 reapiting as a fraction in simplest form

While scuba diving, rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. what expression can be used to find rajeev's new position? 12.6 – 8.7 –12.6 – 8.7 –12.6 – (–8.7) 12.6 – (–8.7)

Ineeeeed this is due tomorrow and i dont know the answer can you find all the exponents

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length