<span>A. (-3, 5)
the equation is xy=-15
or x=-15/y
put y=5
x=-15/5
x=-3</span>
24 inches is i am not mistaking
6 to 12 is +6
12 to 18 is +6
so 18 to 24 is +6
D is a notation for differential. There is a d2 in your formula because in the numerator there are two differentials. The formula is thus the second derivative of a function with respect to two variables.
The answer is b so mark it down
