Answer:
x = 3 and y = -3
Step-by-step explanation:
To start, let's double the first equation to get 6x + 2y = 12. Add this to the second equation to get 10x = 30, so x = 3 and y = -3.
Answer:
Step-by-step explanation:
There are a total of 10 persons (6 teachers + 4 students) from which a committee of 5 is to be formed. This can be done in 10C5 ways.
The number of ways that a committee can be formed with no students in it is to select 5 teachers out of the pool of 6 teachers available. This can be done in 6C5 ways.
Therefore the total number of ways that the committee can be formed with at least one student in it is 10C5 - 6C5.
10C5 = 252
6C5 = 6
Therefore the required number of ways = 246
It's pretty clear what the pattern is - 2^(k-1) * (-1)^(k-1) would work backwards, but we have to work forwards to get lower in this case, so we could start at -3 (as long as we put the k-1 in absolute value to make sure it's not 1/8), so we could write it as ∑ (k=1, goes to 4) 2^(|k-4|)*(-1)^(k-4)
It doesn't matter for k-4 because 1/-1 and 1/1 are the same thing as -1 and 1 respectively
