Answer:
Top right is QI, top left is QII, bottom left is QIII, bottom right is QIV
Step-by-step explanation:
the quadrants start with one at the top left and rotate counterclockwise, rotate to the left
I hope you can see it just try to zoom in
X + y = 40.....multiply by -4
4x + 6y = 180
-------------------
-4x - 4y = -160 (result of multiplying by -4)
4x + 6y = 180
------------------add
2y = 20
y = 20/2
y = 10 <===
x = 30
C is the rigth answer because all the other three has two x values in common. :)