1.8X+2Y+2(5X-2Y)
=8x+2y+10x-4y
=18x-2y
2.7M+3M+3(M+2N)
=10m+3m+6n
=13m+6n
4.2X²-2[3X-2(-X²+2X-1﹚-4]
=2x²-2(3x+2x²-4x+2-4)
=2x²-2(2x²-x-2)
=2x²-4x²+2x+4
=-2x²+2x+4
去括号,在合并同类项.1.8X+2Y+2(5X-2Y) 2.7M+3M+3(M+2N)
去括号,在合并同类项.1.8X+2Y+2(5X-2Y) 2.7M+3M+3(M+2N)
4.2X²-2[3X-2(-X²+2X-1﹚-4]
4.2X²-2[3X-2(-X²+2X-1﹚-4]
数学人气:767 ℃时间:2019-10-19 17:17:18
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