For every function you need evaluate the function for every value in the domain D. And the collection of this values correspond to the range of the function.
1. 
2. 
3. 
4. 
Answer:
100 texts
Step-by-step explanation:
20+.1x=30
30-20=10
10 dollar difference in base prices.
10/.1 (to find out how many texts)
100 texts
Answer:
-4.5
Step-by-step explanation:
The y intercept is where x equals 0