For this set of equations you're going to want to use a process called elimination. In short you can multiply the entire second equation by negative four
-4 (0.2x - 0.3y = 2)
and in turn your equations will now look as follows.
0.8x + y = -9.6 -0.8x + 1.2y = -8
now you may add these two equations together which will leave you with
2.2y = -17.6
divide by 2.2 and then you will end up with
y= -8
and since only one of these answers has a negative 8 as y is can be said that
