Answer:
sin(-pi/2) = -1
Step-by-step explanation:
sin (pi/12) cos((7pi)/12) -cos (pi/12) sin((7pi)/12) = -1
cos(-pi/2) = 0
sin(-pi/2) = -1
cos((2pi)/3) = -1/2
sin((2pi)/3) = (√3)/2
1/5 or -1/9 would both be correct
The second option is the correct cjoice
Answer:

Step-by-step explanation:
The equation for the monthly charge has the following format

In which y(x) is the cost in function of the number of kilowatt-hours used(x), a is the price of each killowatt hour and b is the fixed(base) charge.
Base charge of $17.32 per month.
This means that 
charge of 7.32 cents per kilowatt-hour
Our answer is in dollars. Each dollar is 100 cents. So 7.32 cents is 
Write an equation for the monthly charge y in terms of x, the number of kilowatt-hours used.


Non linear because nothing cubed or squared can be linear.
Hope this helps