25.如圖1,在平面直角坐標(biāo)系中,點(diǎn)A(a,4),點(diǎn)B(-6,0),點(diǎn)C(b,0),且滿足|a+2|+
=0,D為線段BC(含端點(diǎn))上一動(dòng)點(diǎn),將△ACD沿直線AD翻折得到△AED,直線AE交x軸于點(diǎn)F.
(1)求a、b的值以及線段AC的長;
(2)當(dāng)點(diǎn)E落在y軸上時(shí),求點(diǎn)E的坐標(biāo);
(3)當(dāng)△DEF為直角三角形時(shí),請求出滿足條件的點(diǎn)D的坐標(biāo).