Answer:
Plug this in a calculator and the answer will pop up.
Step-by-step explanation:

The classes could each have proportions of 5 boys to 6 girls, but they don’t necessarily have to be exactly 5 to 6. The number could 5 to 6 for one class, but it could also be 10 to 12 for another class, since 10 to 12 is a scale factor of 5 to 6.
Hello from MrBillDoesMath!
Answer:
The first choice ( -12, 20)
Discussion:
Using matrix multiplication we find the equations:
1x + 1y = 8 (A)
2x + 3y = 36 (B)
Next, compute
2(A) - B =>
(2x + 2y) - (2x + 3y) = 2*8 - 36 =>
(2x - 2x) + ( 2y-3y) = 16 - 36 =>
-y = -20 =>
y = 20
Substituting this y value in (A) gives
x + 20 = 8 =>
x = 8 - 20 =>
x = -12
The answer is the first choice ( -12, 20)
Thank you,
MrB
I'm assuming you mean Cartesian plane. It is the same as a coordinate plane. There are two perpendicular lines with an x (horizontal) and y (vertical) axis.