2x+3y=7 (1)3x-5y=1 (2)(1)*5+(2)*310x+15y+9x-15y=35+319x=38x=2代入(1),4+3y=7y=1
2x+3y=7 3x-5y=16x+9y=21 6x-10y=2 19y=19y=1x=2
x=2y=1