Answer:
5 mph
Step-by-step explanation:
The relation between speed, distance, and time is ...
speed = distance/time
Filling in the given values, we find the speed to be ...
speed = (1/4 mi)/(1/20 h) = (1/4)(20/1) mi/h = 5 mi/h
Elena's speed is 5 miles per hour.
To solve these type of problems is to simply invert the number after the division sign and multiply

Answer:
- The first one is 6
x^
3 + 6
x^
2 - 36
x
and the second one is 3x^2 + 21x - 54