Answer:
171
Step-by-step explanation:

Recall that

Take it one piece at a time. For

, we can scale

by -5:

If we shift the argument by 1 and scale by -5, we have

so if we subtract this from

, we'll end up with

For the next piece, we can add another scaled and shifted step like

so that

For the last piece, we add one more term:

and so putting everything together, we get

:

Answer:
190 possibilities.
Step-by-step explanation:
The problem is called 20 choose 2, given by the formula for combinations
C(20,2) = 20! / (2! (20-2)!) = 190
alternatively, we can reason it this way:
there are 20 choices to choose a captain and 19 choices for an alternate captain for a total of 380 ways.
However, there are 20 choices to choose an alternate captain and 19 choices for a captain for a total of 380 ways.
Since we are essentially double counting every choice of the posts, we need to divide 380 by 2 to get 190 ways.
9/10(3x+12y+-6z) is the expression, simplified it's:
2.7x+10.8y-5.4z
Hope this helped!
Answer:
B
Step-by-step explanation:
y = 5x
check your work by plugging in the values
y = 5(1)
y = 5 yes
y = 5(2)
y = 10 yes
y = 5(3)
y = 15 yes
y = 5(4)
y = 20 yes