初中数学专题：二次函数知识要点

12yaxbxcabc0a0abc2.2yaxbxcxx2abcabc1.2yax2.2yaxc3.2yaxma0a00y0xyx0xyx0xy00a00y0xyx0xyx0xy0a0a0cy0xyx0xyx0xyc0a0cy0xyx0xyx0xycay=2x2-4y=2x2+2y=2x24.2yaxmk1.0a0mX=mxmyxxmyxxhy00a0mX=mxmyxxmyxxhy0a0amkX=mxmyxxmyxxhyk0amkX=mxmyxxmyxxhyky=3(x+4)2y=3(x-2)2y=3x22yaxmkmk2yaxmk2.hk2yaxmk2yaxbxc2yaxmk2yaxbxc22424bacbyaxaa2424bacbmkaa2yaxmkmk2yaxbxc24()24bacbaa2yaxbxc2yaxbxc2yaxmk.y0c0c2mcx10x20xx.xy.2yaxbxc1.0a2bxa2424bacbaa2bxayx2bxayx2bxay244acba2.0a2bxa2424bacbaa2bxayx2bxayx2bxay244acba1.2yaxbxcabc0a2.2yaxmkamk0a3.12()()yaxxxx0a1x2xx.x240bac.1.a2yaxbxca0a0aaa0aaaaaa2.bab0a0b02bay0b02bay0b02bay0a0b02bay0b02bay0b02bayabababx2y0aby0ab3.c0cyxy0cyy00cyxycy1.2.3.x4.