①*3 is 9x+ 12y = 6k-9③.

② 4x-2y of * 2 = 6k+8④

③-④ 5x+ 14y+ 17 = 0。

So y =-(5x+ 17)/ 14.

Because x+y = 2

So x-(5x+ 17)/ 14 = 2.

The solution is x = 5.

So y =-3.

Substitute into ① to get k = 3.

2. According to the meaning of the question, the positive solutions of the equations are x = 3 and y =-2.

So 3c+ 14 = 8.

Get c =-2.

Substitute x = 3 and y =-2 into ax+by = 2 to get 3a-2b = 2.

Because B just copied C wrongly, it has no effect on the first equation.

So the solution of b also satisfies AX+BY = 2.

So -2a+2b = 2.

The solution is a = 4 and b = 5.