1.2x+3y=1(1) 2.6x=3y-3(1) 3.3x+y=4(1)3x-5y=-8(2) 5x-9y=-35.3(2) 2x-3y=-1(2)(1)*3得 原方程组化为 (1)*3得6x+9y=3(3) 3y-6x=3(3) 9x+3y=12(3)(2)*2得 5x-9y=-35.3(2) (2)+(3)得6x-10y=-16(4) (3)*3+(2)得 11x=11...