Plz ASAP I need help really important

Select the correct answer from each drop-down menu. rewrite the formula to find voltage. the formula for electrical power (p, in watts) is where v is the voltage in volts and r is the resistance in ohms. for a particular brand of water heater, r is 32 ohms and p is 0.5 watts. the formula to find v is , and the voltage at which the heater operates is volts.

How to do this , and can some one explain

If y varies directly as x2 and y=6 when x=6, find the constant of variation.