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!
Answer:
x = 4
Step-by-step explanation:
x + 4(x+5) = 40 (Given)
x + 4x + 20 = 40 (Distribute the 4 into the x and 5)
5x + 20 = 40 (Add like terms)
5x = 20 (Subtract 20 on both sides)
x = 4 (Divide 5 on both sides)
Answer:
An hour and 30 minutes.
Step-by-step explanation:
In one hour, they travel 8 kilometers. They then have 4 kilometers left. 4 is half. of 8, so I would possibly take half the time it would to travel 8, making it 30 minutes for the other 4 kilometers.
Answer:
see explanation
Step-by-step explanation:
Simplify the radical
= 
= 
Square both sides
T² = ( multiply both sides by (g + f) )
T²(g + f) = Ufg ( distribute left side )
T²g + T²f = Ufg ← subtract Ufg from both sides
T²g - Ufg + T²f = 0 ← subtract T²f from both sides
T²g - Ufg = - T²f ← factor out g from each term on the left side
g(T² - Uf) = - T²f ← divide both sides by (T² - Uf)
g = - 
= 
Answer: x=-14
Step-by-step explanation:
