(2)3y-2z = 1 times 3 to get 9y-6z = 3;; 4x+9y= 12 minus 9y-6z=3 to get 4x+6z = 9;; 4x+6z=9 times 7 to get 28x+42z=63, 7x+5z= 19/4 times 4 to get 28x+20z =19; The sum of the two formulas gives 22z=44, and the solution gives z=2. Substituting them into the solution, X =-3/4 and Y = 5/3 are obtained respectively.