To annoy everyone and make life hard as heck. There is no true purpose behind it and teachers just like to make everyone's home life 10x more annoying. They also do it because 99% of teacher are crazy cat people with no life. So for them homework keeps them busy
9514 1404 393
Answer:
x ∈ (-∞, 9) U (-1, ∞)
Step-by-step explanation:
Get the absolute value by itself. Do that by multiplying by 4.
|3x +15| > 12
This resolves to two cases:
<u>3x +15 > 12</u>
x +5 > 4 . . . . divide by 3
x > -1 . . . . . . .subtract 5
<u>-(3x +15) > 12</u>
x +5 < -4 . . . . divide by -3
x < -9 . . . . . . . subtract 5
Then the solution in interval notation is ...
x ∈ (-∞, 9) U (-1, ∞)
18 choose 7
=C(18,7)
=18!/(7!(18-7)!)
=31824
OR
18 choices for first passenger,
17 choices for second passenger,
....
12 choices for 7th passenger,
so total = 18*17*16...12
but there are 7! ways to order the 7 passengers, so
number of groups
=18*17*16...12/7!
=31824 as well
