Answer:
C
Step-by-step explanation:
Answer: 3 mi/h
Step-by-step explanation:
Here we have to find the speed 
at which Sarah walks to school, knowing the distance 
she has walked and the time 
she expends.
So, in this case we can use the following equation:
Where:
Solving:
This is Sarah's speed
The set of all output values for a function is called the range.
4a-8=28
add 8 to both sides to start to isolate the variable (a)
-8+8 cancels each other out
28+8=36
4a=36
to completely isolate the variable divide both sides by 4
4a÷4=a
36÷4=9
a=9
