Kendall's brother, arnold bought a plate at this store, and he also payed 3% in sales tax. arnold paid a total of 0.72 in sales tax. what was the price of the plate arnold bought without sales tax? explain and show work

Im really not sure what the exact answer is 

-|x| means that the value of x will be negitive due to the negitive sign on the outside. But |-x| that has a negitive sigh inside and the two lines that are on the outside on the -x is to make the number inside positive. So the first one will be -x at the end. The second one will be just x