Let's solve this thru elimination. Starting with x + y = 1, subtract x from both sides, obtaining y = 1 - x. This yields 2x - 3(1 - x) = - 30.
Performing the multiplication, we get 2x - 3 + 3x = -30.
Combining like terms: 5x = -27, or x = -27/5.
We already know that y = 1 - x. Thus, y = 1 - (-27/5), or y = 32/5.
The solution set is (-27/5, 32/5).