This is given by the multinomial coefficient:

If you're not familiar with the multinomial coefficient, you may be able to see it more clearly if you count the number of possible combinations taking each distinct letter

times, where

is the number of times it shows up in the original word.
Answer:
Only choices C and D are solutions
Step-by-step explanation:
6x + 3y = -15
y = -2x - 5
6x + 3y = -15
6x + 3(-2x - 5) = -15
6x - 6x - 15 = -15
0 = 0
Since 0 = 0 is a true statement, both equations of this system are the same equation and represent a single line on the coordinate plane.
We need to check each choice in just one equation.
Let's use the second equation.
y = -2x - 5
A.
(2, 7)
7 = -2(2) - 5
7 = -4 - 5
7 = -9 False
Not a solution
B.
(5, 0)
0 = -2(5) - 5
0 = -10 - 5
0 = -15 False
Not a solution
C.
(-3, 1)
1 = -2(-3) - 5
1 = 6 - 5
1 = 1 True
Solution
D.
-13 = -2(4) - 5
-13 = -8 - 5
-13 = -13 True
Solution
Answer: Only choices C and D are solutions
B. Yes, because it passes the vertical line test.
Neither one will ever hit the axis I think? if its x=3.5 then its horizontal but its above the x axis. Same with the second one. its vertical and will never hit the y axis. Not sure how to write that into those boxes but I think there isn't an intercept.