试证明代数式-(a-23)-{10a-[5a-15-(4-6a)]}的值与a的取值无关.

问题描述:

试证明代数式-(a-23)-{10a-[5a-15-(4-6a)]}的值与a的取值无关.

-(a-23)-{10a-[5a-15-(4-6a)]} =-a+23-{10a-[5a-15-4+6a]} =-a+23-{10a-11a+19} =-a+23+a-19 =23-19 =4 与a的取值无关