Answer:
substitute -10 for x and -20 for y
-10-20 / -20
-30/-20
1 1/2
Answer:
There is no slope. 
Step-by-step explanation:

(2, 2) and (4,2) makes a horizontal line. All horizontal lines on a graph have no slope.
Answer:
The value of 1/2 over 8 is 4.
Step-by-step explanation:
1. how much to tip
2. how much interest is needed for a loan
3. figuring out how much sales tax
Answer:
- 4m - 2r - 25
Step-by-step explanation:
-8m + (-15) + 4m - 2r - 10
- 8m - 15 + 4m - 2r - 10
collect the like terms beginning with the positives
4m - 8m - 2r - 10 - 15
- 4m - 2r - 25