二分之m乘6+三分之n乘6=13乘63m+2n=78(2)三分之m乘12-四分之n乘12=3乘124m-3n=36方程组:{(1)3m+2n=78;(2)4m-3n=36(1)3m*3+2n*3=78*39m+6n=234(2)4m-3n=364m*2-3n*2=36*28m-6n=72方程组:{9m+6n=234;8m-6n=729m+8m=234...