1）抱歉。题目看不清。2)根据定义|n+1|=1 所以n=0或-2那么化简原方程3x+2x-7=8 得x=33）化简方程的8x+2k=20即4x+k=10又方程有正整数解，且k为正整数，那么k=6或2欢迎采纳（这确定是六年级的题么）
jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
你确定这是六年级？？
