（1）y=-(x-4/3)²/4+4/9,對(duì)稱軸x=4/3,點(diǎn)d的坐標(biāo)(4/3,0)；
（2）拋物線與y軸交點(diǎn)(0,0),設(shè)向上平移h,y=-x²/4+2x/3+h,則與y軸交點(diǎn)(0,h),∠acb=90°,h²=|x1x2|,x1x2=-4h,h=4,拋物線的解析式：y=-x²/4+2x/3+4.
（1）y=-x²/4 +3x/2=-(x-3)²/4+9/4,對(duì)稱軸x=3,點(diǎn)d的坐標(biāo)(3,0)；
（2）拋物線與y軸交點(diǎn)(0,0),設(shè)向上平移h,y=-x²/4 +3x/2+h,則與y軸交點(diǎn)(0,h),∠acb=90°,h²=|x1x2|,x1x2=-4h,h=4,拋物線的解析式：y=-x²/4+3x/2+4.