9. If the exponents of X and Y are both 1, the equations about A and B can be obtained and solved directly;

10, let 2x-3y+5=0, x+y-2=0, and get the simultaneous solution;

1 1, directly substitute x=a, y=b to get the equations about a and b, and directly solve them;

12, according to the meaning of the question, substitute x=-3 and y=- 1 into formula 2 to get b; X=5 and y=4 are substituted into 1 to get a; Then substitute a and b into the original equation to get the values of x and y.