I would help you but I can't see it maybe zoom in a little closer.
There would be 12 people at the party!
In general, with n+1 people, the number of handshakes is the sum of the first n consecutive numbers: 1+2+3+ ... + n.
Since this sum is n(n+1)/2, we need to solve the equation n(n+1)/2 = 66.
This is the quadratic equation n2+ n -132 = 0. Solving for n, we obtain 11 as the answer and deduce that there were 12 people at the party.
Since 66 is a relatively small number, you can also solve this problem with a hand calculator. Add 1 + 2 = + 3 = +... etc. until the total is 66. The last number that you entered (11) is n.
Hope this helps!
C is the answer cause 9 is the common factor
-15+5x= 20
5x= 35
x= 7
20= -15+5x
35= 5x
7 = x
Answer:
s
Step-by-step explanation:
sdd
