Answer:
14
Step-by-step explanation:
Since gaining fourteen pounds means going in a positive direction, we can say the gain of fourteen pounds numerically as 14.
Loretta:
Average driving speed = 55 mph
Time = 4 hours
Distance traveled = 55*4 = 220 miles
Dad:
Average driving speed = 65 mph
Let x = hours driven
Distance traveled = 65x miles
The length of the trip is 610 miles, therefore
65x + 220 = 610
65x = 390
x = 6 hours
Answer: Loretta's dad drove for 6 hours.
Get everything on one side:

. Now we can factor to find the solutions. What we ask ourselves here is "What 2 numbers will add to be +4 and multiply to be -21?" +7 and -3 work because 7-3 = 4 and 7 * -3 = -21. So our factors are (x+7)(x-3). Our solutions, however, are found using the Zero Product Property. If x + 7 = 0, then x = -7. If x - 3 = 0, then x = 3. So our solutions are x = -7 and x = 3.