T is greater than -15 because numbers after -15, like -16... are less than -15, so when its decreasing it gets lower. Since the questions says the temp stayed above -15, that means the temp could be -14...-13 and so on.
The answer should be 9 rounded because 2 pi r 56.5 will give u that.
This question is super easy, all you need to do is isolate the y variable. When you want to isolate it, you have to get rid of other numbers by doing the opposite sign.
x+2y=8 Subtract the x.
2y=8-x Divide by two.
y=4-1/2x