If the equation of a line is 4x + 4y = 1 and equation of a second line is x + y = -8 which of the following is true
1 answer:
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Answer:
Step-by-step explanation:
1. By definition, you have if , then
2. Keeping this on mind, you must follow the proccedure shown below:
- You have that:
Where:
- Substitute values into . Then, you obtain:
Answer:
Step-by-step explanation:
Amount of brine = 100 gal
amount of salt = 80 lb
rate of water running = 4 gal / min
Let A be the amount of salt in lb in the tank at any time t.
(a) dA/dt = rate of salt in - rate of salt out
Rate of salt in = 0
rate of salt out = A x 4 / 100 = A / 25 lb/min
So, dA/dt = 0 - A/25 = - A/25 lb/min
When t = 0, A = 80 lb
So,
(b) Now, A = 40 lb
So,
take log on both the sides
t = 17.3 minutes