Problema Solution

A scientist wants to research the potential spread of germs by contact. she knows that the number of possible handshakes within a group of n people is given by the equation N=1/2(n^2-n)

how many people attended the party?

Answer provided by our tutors

N= 1/2 (x squared minus x)

N= 78

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Solve for "x":

(1/2)(x^2-x) = 78

x^2-x = 156

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x^2-x-156 = 0

Factor:

(x+12)(x-13) = 0

Positive solution:

x = 13