先化简,再求值:3n-[5n+(3n-1)],其中n=6

问题描述:

先化简,再求值:3n-[5n+(3n-1)],其中n=6

3n-[5n+(3n-1)] = 3n-(8n-1) = -5n+1 = -5*6+1 = -30+1 = -29