Answer:
The slope is 
Step-by-step explanation:
Take the general equation of a straight line 
Here
is the slope of the line.
So let's get the equation of the line in the question in the same form.

Add
to both sides: 
Add
to both sides: 
Divide by
to get it into the general equation: 
Now compare it to the general equation to find the value of
. The value of
is the coefficient of
which we can see is 
Newton's Law of Cooling
Tf=Ts+(Ti-Ts)e^(-kt) where Tf is temp at time t, Ts is temp of surroundings, Ti is temp of object/fluid. So we need to find k first.
200=68+(210-68)e^(-10k)
132=142e^(-10k)
132/142=e^(-10k)
ln(132/142)=-10k
k=-ln(132/142)/10
k≈0.0073 so
T(t)=68+142e^(-0.0073t) so how long until it reaches 180°?
180=68+142e^(-0.0073t)
112=142e^(-0.0073t)
112/142=e^(-0.0073t)
ln(112/142)=-0.0073t
t= -ln(112/142)/(0.0073)
t≈32.51 minutes
D
You subtract 5 1/4 (5.25) - 3 3/4 (3.75) = 1 1/2 (1.5)
This equation simplified is: