Each shows two lines that make up a system of equations. If the graphs of the equations intersect, then there is one solution that is true for both equations. If the graphs of the equations do not intersect (for example, if they are parallel), then there are no solutions that are true for both equations.
Just plug in 3 for n and then 5 for n to see if an turns out to be 10 and 26.
n=3:
A) an = 8*3+10 = 34
B) an = 8*3 - 14 = 10 OK
C) an = 16*3+10 = 58
D) an = 16*3 - 38 = 10 OK
n=5:
B) an = 8*5-14 = 26 OK
D) an = 16*5 - 38 = 42
So the answer is B
When x=-1:

Ok that gives us a little more information.
If we implicitly differentiate with respect to t, from the very start, then we can apply our product rule, ya?

The right side is zero, derivative of a constant is zero.
Where x' is dx/dt and y' is dy/dt.
From here, plug in all the stuff you know:
y' = -3
x = -1
y = 4
and solve for x'.
Hope that helps!
Answer:
Undefined
Step-by-step explanation:
This is horizontal line, so the slope is undefined.