题目(1)(1)(1)计算:(3a+1−a+1)÷a2−4a+4a+1(\frac{3}{a+1}-a+1)÷\frac{{a}^{2}-4a+4}{a+1}(a+13−a+1)÷a+1a2−4a+4；(2)(2)(2)先化简(1−1x−1)÷x2−4x+4x2−1(1-\frac{1}{x-1})\div \frac{{x}^{2}-4x+4}{{x}^{2}-1}(1−x−11)÷x2−1x2−4x+4,再从不等式2x−1<62x-1 \lt 62x−1<6的正整数解中选一个适当的数代入求值.知识点：分式的化简求值章节：数与式 / 分式
