Question

【题目】（本小题满分9分）证明代数式16+a–{8a–[a–9–（3–6a）]}的值与a的取值无关．

Answer 1

【答案】见解析

【解析】∵原式=16+a–{8a–[a–9–3+6a]}

=16+a–{8a–[7a–12]}

=16+a–{8a–7a+12}

=16+a–{a+12}

=16+a–a–12

=4．

∴代数式的值为4，与a的取值无关．