“ｘ＝１”和“ａ＋ｂ＝ｂ＋ａ”是方程吗在一次数学竞赛的试题中，有这样一道题目：下面几个式子，（）是方程。①４＋７ｘ＝１８；②３ｘ－５；③ｘ＝１；④６＋１０＝１６；⑤ａ＋ｂ＝ｂ＋ａ；⑥５ｘ－５＜６。毫无疑问，①式是方程。有的同志认为：③式和⑤式也是方程... Is the equation “x = 1” and “a + b = b + a”? In a mathematical contest question, there is such a question: the following formulas, () is the equation. ① 4 + 7x = 18; ② 3x-5; ③ x = 1; ④ 6 + 10 = 16; ⑤ a + b = b + a; ⑥ 5x-5 <6. There is no doubt that ① equation is equation. Some comrades think: ③ type and ⑤ type is also an equation ...