(x+2)(y+3)-(x+1)(y-2) 這道題怎麽?便運算
热心网友
(x+2)(y+3)-(x+1)(y-2) =［(x+1)+1］(y+3)-(x+1)(y-2)=(x+1)(y+3)-(x+1)(y-2)+y+3=(x+1)(y+3-y+2)+y+3=5×(x+1)+y+3=5x+y+8
热心网友
什么简便方法哦 ,一点也没有减少解答步骤.最简单的就是直接算拉. 用这种方法花的时间更多.
热心网友
原式＝（xy+3x+2y+6)-(xy-2x+y-2) =xy+3x+2y+6-xy+2x-y+2 =5x+y+8
热心网友
是（x+2)*(y+3)=(x+1+1)*(y+3)=(x+1)*(y+3)+1*(y+3)
热心网友
(x+1)(y+3)-(x+1)(y-2)+y+3=(x+1)(y+3-y+2)+y+3=(x+1)*5+y+3=5x+y+8