So you have to divide the amount by how many you’re buying and get the unit rate per each ounce so the answer is b
Unsure of what you mean by "reference number."
I do recognize that 11pi/9 is in quadrant III. I suspect that the so-called "reference number" is the acute angle between the end ray of 11pi/9 and pi, or, in more easily comparable numbers, between 9pi/9 and 11pi/9.
That difference is 2pi/9.
Answer:

Step-by-step explanation:
The given quadratic trinomial is 
Where a=6, b=-13 and c=-5

The factors of -30 that add up to -13 are -15,2
We split the middle term to get:

Factor by grouping:

These completely factors to:

By using this example you be able to do it