许多有关中学数学教学的权威文献都涉及到了方程 f_1(x)·f_2(x)=0的解集问题:(1)高级中学课本《代数》上册(必修)在引入并集的概念和解释并集的一个应用时写到:方程(x~2-4)·(x~2-1)=0的解集,可以从求方程 x~2-4=0的解集与方程 x~2-1=0的解集的并集而得到.这句话是学生 Many authoritative literatures on mathematics teaching in middle schools have addressed the problem of the solution set of the equation f_1(x)·f_2(x)=0: (1) The concept and interpretation of the union are introduced in the upper secondary school textbook “Algebra” on the first volume (required). An application of the set writes: The solution set of the equation (x~2-4)(x~2-1)=0 can be obtained from the solution set of the equation x~2-4=0 and the equation x~2-. The union of 1 = 0 solution sets is obtained. This sentence is a student