方程两边同时加上或者减去相同的数,等式保持不变.x + 0.58 = 12.64 3.2 + x = 10.8 x - 6.2 = 7.8 x - 1.5 = 4 方程两边同时乘上或者除以相同的数,等式保持不变.5x =6.5 0.2x = 6.2 x ÷ 3.2 = 2.5 x ÷ 6 = 10.9 先...