1.X-5y=2乘3即3x-15y=6减3x+2y=23得17y=17;:y=1;x=7;2.m/2+n/3=1乘6得3m+2n=6,m/3-n/6=11/6乘6得2m-n=11乘2后得4m-2n=22然后和上式相加就解得.