Answer:
A,B, C
Step-by-step explanation:
hope it helps
This is the concept of algebra, to solve the expression we proceed as follows;
cos 2x-cosx=0
cos 2x=cosx
but:
cos 2x+1=2(cos^2x)
thereore;
from:
cos 2x=cos x
adding 1 on both sides we get:
cos 2x+1=cos x+1
2(cos^2x)=cosx+1
suppose;
cos x=a
thus;
2a^2=a+1
a^2-1/2a-1/2=0
solving the above quadratic we get:
a=-0.5 and a=1
when a=-0.5
cosx=-0.5
x=120=2/3π
when x=1
cos x=1
x=0
the answer is:
x=0 or x=2/3π
If a is the number of events, then a = 1. Plugging in 1 for a in the equation

, you get

.
Total cost is $9.
H + 121 + 31 = 180
H + 152 = 180
H = 180 - 152
H = 28
I think 5?
These are the ages,
12, 12, 14, 15, 17,
28, 29,
40, 41, 44, 45,
50,
69
Only the people on the first row are under 19 and there are 5 people.