(x+2)(y+3)-(x+1)(y-2) 這道題怎麼?便運算
熱心網(wǎng)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
熱心網(wǎng)友
什么簡便方法哦 ,一點也沒有減少解答步驟.最簡單的就是直接算拉. 用這種方法花的時間更多.
熱心網(wǎng)友
原式＝（xy+3x+2y+6)-(xy-2x+y-2) =xy+3x+2y+6-xy+2x-y+2 =5x+y+8
熱心網(wǎng)友
是（x+2)*(y+3)=(x+1+1)*(y+3)=(x+1)*(y+3)+1*(y+3)
熱心網(wǎng)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