Acustomer pay 18 for a dvd that originally cost 20. what is the percent decrease in the cost of the dvd

The discount is $2. 2/20 is 0.1 or 1/10 which as a percentage would be 10%. The discount of $2 is 10% off.

y=−9/2x+10

step-by-step explanation:

let's solve for y.

0−9x−2y=−20

step 1: add 9x to both sides.

−9x−2y+9x=−20+9x

−2y=9x−20

step 2: divide both sides by -2.

−2y

−2

=

9x−20

−2

y=

−9

2

x+10