Answer:
66
Step-by-step explanation:
If there are <em>n</em> students, then the number of pairs is 
.
With 12 students, 
pairs can be formed.
The reason the formula works is this: Each of the 12 students can be paired with 11 other students (no student is paired with him/her self). But counting 12 x 11 = 132 counts each pair <u>twice</u>. Example: student A can be paired with student B,..., student B can be paired with student A. The pair was counted two times.
See the attached image that shows pairings of 5 students. There are
5(5 - 1)/2 = 5(4)/2 = 10 pairs.
Answer: False
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Explanation:
I'll use x in place of p.
The original equation 10x^2-5x = -8 becomes 10x^2-5x+8 = 0 after moving everything to one side.
Compare this to ax^2+bx+c = 0
We have
Plug those three values into the discriminant formula below
d = b^2 - 4ac
d = (-5)^2 - 4(10)(8)
d = 25 - 40*8
d = 25 - 320
d = -295
The discriminant is negative, which means we have no real solutions. If your teacher has covered complex or imaginary numbers, then you would say that the quadratic has 2 complex roots. If your teacher hasn't covered this topic yet, then you'd simply say "no real solutions".
Either way, this quadratic doesn't have exactly one solution. That only occurs when d = 0. Therefore, the original statement is false.
This is all I got sorry if it don’t help
3x+5y=16 is linear equation........
Money spent + money left over = total money
money spent + 9 = 30
We don't know the price of each shirt, so let x = price of 1 shirt.
Then, 3 shirts cost 3 times as much as x, or 3x.
She spent 3x.
3x + 9 = 30
