The correct answer is the first option.
If you want to use elimination, you can sum the two equations for example, so that the x's simplify:



Plug this value for y in one of the equations to derive the value of x:

So, the solution is 
The formula for the volume of a cone is
v = ( 1 / 3) h pi r^2
where h is the height of the cone
pi is 3.1416
r is the radius of the cone
since diameter is given
D = 2r
r = D/2 = 4/2 = 2 in
substitute the given
V = (1/3) (6) (3.1416) (2^2)
V = 25.1 cubic in
Answer:
C
Step-by-step explanation:
note that sin x = cos(90 - x ) ← Cofunction identity
If x = 36 then 90 - x = 90 - 36 = 54
Hence sin 36° = cos 54° → C
I believe it is -81k^2
-27k^3-81k^2-81k-27
You'll need to provide a bit more information for me to answer this. I.e are you trying to find out how much money will be made after a certain number of years? e.c.t