去括号并合并同类项(1)3x-2(x+7)+2(2x+5) (2)(4x-3y)-[-(3y-x)+(x-y)]-5x

问题描述:

去括号并合并同类项(1)3x-2(x+7)+2(2x+5) (2)(4x-3y)-[-(3y-x)+(x-y)]-5x


3x-2(x+7)+2(2x+5)
=3x-2x-14+4x+10
=(3x-2x+4x)+(10-14)
=5x-4
(4x-3y)-[-(3y-x)+(x-y)]-5x
=4x-3y-[-3y+x+x-y]-5x
=4x-3y+4y-2x-5x
=(4x-2x-5x)+(4y-3y)
=-3x+y真的正确吗第2题4y哪来的(4x-3y)-[-(3y-x)+(x-y)]-5x=4x-3y-[-3y+x+x-y]-5x-(-4y+2x)4y-2x=4x-3y+4y-2x-5x算了,算了,看不懂,直接抄上去把,3Q???把这道题采纳了,不懂就问