Simutaneous equation by substitution: y+2x=0,4x+y= for x and y

1y + 2x = 0 ⇒ -2x - 1y = 0
4x + 1y = 3 ⇒  4x + 1y = 3
                                2x = 3
                                 2     2
                                  x = 1.5
                     4(1.5) + y = 3
                            6 + y = 3
                         - 6        - 6
                                  y = -3
                            (x, y) = (1.5, -3)

I’m guessing that the answer is c, but i’m not sure which grid is being talked about. since 5x5= 25 and 3x3= 9 (which there are no answers for). a is not right because while the ratio is the same, 6/25= 0.24 which is equal to 24% not 30%.