One week jenna rented 4 dvds and 2 video games for $18, the next week she rented 2 dvds and 1 video game for 9$. find the rental costs for each video game and dvd. explain you answer.

To do this problem you have to create two equations. one would be 18=4x+3y
an the other would be 9=2x+y. in this eqaution X is the number of DVDs and Y is the number of Video games. Then you solve for Y in the second equation and you get y=-2x+9. After that you then input this equation in for the other equation and you will have 18=4x+3(-2x+9). you solve for X in this problem and then you take the answer of x and put it in for x in the other equation. 
so, 18=4x-6x+27
subtract 27 and add the 4x and -6x
-9=-2x
x=4.5
after this you put it in the other equation
9=-2(4.5)+y
multiply the -2 and 4.5
9=-9+y
add the 9
y=0