The answer to your problem is A due to the slope of your line being -1/3x.
You can find this slope by picking two points on your graph [i.e. (-1,3) and (0,0)].
Find the difference between the two points, which is a one for the x value and a three for the y values. Now you have a slope of 1/3.
But wait! The slope is downwards, therefore a negative must be applied to your slope.
This provides you with a slope of -1/3x, therefore:
y = -1/3x
42 6 7 times is 42 so the answer will be 42
X-intercept is (-6, 0) , (3, 0)
Yeah it really be like that sometimes, you gotta try girl
A) The differential equation comes from the fact that the rate of temperature change is proportional to the difference in temperatures.

B) Find general solution by separating variables and integrating

:
C) Initial condition is t=0, T = 87

D) Total time elapsed is 10 minutes, new temperature is 84

solve for alpha

E) Temperature function is:

solving for t

Plug in T = 98.6

This is approximately 32 minutes before he arrived or about 1:20 AM