Help with this pls

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

Type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar. a city water tank holds 20 gallons of water. a technician empties 25% of the tank. how many more gallons of water must be removed from thetank so that it has 5 of the water that it started with: the technician must removemore gallons of water for the tank to have 5 of the water that it started with.

Simplify each expression. use positive exponents. show work . (x –2 y –4 x 3 ) –2