Answer: The expression is undefined for x=4 and x=5.
The expression is undefined for any x that makes the denominator 0. This leads to solving a quadratic equation:

(5/6) / (1/4)
5/6 * 4/1
20/6
3 1/3 <=== there is 3 1/3 one-forth lb servings
Answer: 0.3m/s
Step-by-step explanation:
Height/ velocity
3m/12m per sec
Time= 0.25metres per seconds
To the nearest tenth, 0.3m per seconds

keep in mind that, a negative coefficient to "x", will make the graph reflect over the y-axis.
The answer is:t=4 You welcome