這問題不難.該題應(yīng)該設(shè)頂點(diǎn)式求,即知道頂點(diǎn)坐標(biāo)和任一點(diǎn)坐標(biāo)可求解析式.拋物線y=-2x^2-4x+1的頂點(diǎn)坐標(biāo)為（-1,3）,則（-1,3）關(guān)于X軸的對(duì)稱點(diǎn)應(yīng)該是（-1,-3）,所以關(guān)于x軸對(duì)稱的拋物線的頂點(diǎn)坐標(biāo)是（-1,-3）,再在拋物線y=-2x^2-4x+1上任找一點(diǎn),如當(dāng)X=2時(shí),Y＝-15,即（2,-15）在y=-2x^2-4x=1上,那么（2,-15）關(guān)于X軸的對(duì)稱點(diǎn)坐標(biāo)是（2,15）,設(shè)拋物線的解析式為y=a(x-h)^2+k,把（-1,-3）代進(jìn)去得y=a(x+1)^2-3,再把（2,15）代進(jìn)去,得15=a(2+1)^2-3,解得a=2,再把a(bǔ)=2代回y=a(x-1)^2-3得y=2(x+1)^2-3,化為一般式即得拋物線解析式是y=2x^2+4x-1
提個(gè)醒：不是用平移的知識(shí),這道題的知識(shí)點(diǎn)是（x,y)關(guān)于x軸的對(duì)稱點(diǎn)是（x,-y).