The answer to your question is A
Y=1/16x^2
multiplying both sides by 16 we get:
16y=x^2
The general form of a parabola is:
(x-h)^2=4p(y-k)
thus
4p=16
p=4
The parabola opens upwrd:
Focus: (h,k-p)
(0,0-4)
=(0,-4)
Directrix: y=-4
The value of m is -30 because once you get m on the one side the equation is 3m=-90 and once you divide -90 by 3 you get m=-30.
The change in temperature for 1 hour would be -5. hope this helps.