解:依题意得方程组,x+y=100 (1)x-y=50 (2)(1)+(2)得x+y+(x-y)=100+50x+y+x-y=1502x=150x=150÷2x=75将x=75带入(1)得75+y=100y=100-75y=25即x=75,y=25