Answer:

Step-by-step explanation:
Given
Represent number of DVDs with x


(at most)
Required
Represent as an inequality
If 
x DVD would cost:


So, to make an order of x DVDs, Deacon will pay for
x DVDs and Handling Fee
So:

Recall that his budget is at most $75
This implies that: 
So, the relationship between his payment and budget is:

Answer:
.80x
Step-by-step explanation:
If the price is reduced by 20% we are paying 100-20 or 80 percent
The new price is
x* 80%
.80x
Answer:
2000
Step-by-step explanation:
Increase 1000 by 1000 in addition.
Modeled in an equation, the situation is 1000 + 1000.
1000 + 1000 = 2000
First:
2x + 2z = 4
2(x+z)=4
x+z=4/2
x=2-z
-x - y - z= -8
-(2-z)-y-z= -8 replace x
-2+z-y-z= -8 (cancel z)
-2-y= -8
6 = y
Then:
-4x + 4y + 5z = 7 replace x and y
-4(2-z)+4*6 + 5z = 7
-8 + 4z + 24 + 5z = 7
16 + 9z = 7
9z = 7 - 16
9z = -9
z = -9/9
z= -1
Finally
x= 2-z replace z
x = 2- (-1)
x = 3