This is easy basically what you're going to do is that you have 5 friend and you only have 2 bags of Trail Mix that would make it 2 / 5
For the order of operation use PEMDAS
Parenthesis
Exponent
Multiplication
Division
Addition
Subtraction
For memorizing the order you could say
Please
Excuse
My
Dear
Aunt
Sally
The equation would be 4n=8000
to solve, divide 8000/4=2000, she has collected 2,000 signatures so far
8-3x
Divide the whole thing by 2 so it would be y=4-1.5x
An=-31+(n-1)-11 find the eleventh term
a11 = -31 + (-11) (11-1)
a11 = -31 +-11(10)
a11 =-31 +-110
a11 = -142