4X-(X-1)=4X+(-1)(X-1)这步是怎么算的?请写出过程和结果,然后下一步4X+(-1)X+(-1)(-1)这一步又是怎么算
问题描述:
4X-(X-1)=4X+(-1)(X-1)这步是怎么算的?请写出过程和结果,然后下一步4X+(-1)X+(-1)(-1)这一步又是怎么算
答
因为-(X-1)=(-1)(X-1)
所以4X-(X-1)=4X+(-1)(X-1)
因为(-1)(X-1)=(-1)X+(-1)(-1)
所以4X-(X-1)=4X+(-1)(X-1)=4X+(-1)X+(-1)(-1)