First we determne the values we will need for Cramer's Rule:

a₁ = 1 b₁ = -3 c₁ = 6

a₂ = 2 b₂ = 3 c₂ = 3

So the solution is (3, -1).

Check: [1] 3 + 3 = 6 OK

[2] 6 - 3 = 3 OK