Respuesta :
To figure out what one DVD would cost, we take our information "$21 for 3 DVD's." All you have to do here is do $21 divided by 3 DVD's to find that one DVD is $7.
If Chiara wants to purchase 9 DVD's next time and needs to know the money, we take our previous information (1 DVD = $7) and input it into this equation.
x (unknown dollars) = 9 (DVD) * 7 ($).
Meaning that 9 * 7 = 63.
It will cost $63 for 9 DVD's, when 1 DVD is $7.
If Chiara wants to purchase 9 DVD's next time and needs to know the money, we take our previous information (1 DVD = $7) and input it into this equation.
x (unknown dollars) = 9 (DVD) * 7 ($).
Meaning that 9 * 7 = 63.
It will cost $63 for 9 DVD's, when 1 DVD is $7.