You must calculate how many ways can 2 people be selected from 65.
The formula is:
n! / r! * (n-r)! =
65! / 2! * 63! =
65*64*63! / 2 * 63! =
65*64 / 2 =
2,080 handshakes
Source:
http://www.1728.org/combinat.htm
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(0,-1)(1,4)
slope = (4 - (-1) / (1 - 0) = (4 + 1)/1 = 5
y = mx + b
slope(m) = 5
(1,4)...x = 1 and y = 4
now we sub
4 = 5(1) + b
4 = 5 + b
4 - 5 = b
-1 = b
equation is : y = 5x - 1...answer C
0.50x+25 would be the expression form of the situation
2x-3y=4
x+4y=-9/*(-2)
2x-3y=4
-2x-8y=18
-11y=22/:(-11)
y=-2
x+4*(-2)=-9
x-8=-9
x=-1
I hope this helped.
