5.C.y=-4(x+2)2+4D(11)2—x一―A-18B18C-12y=(x:+2L-3y=x2A.23B.23D1-4()88A.2B.4C.69ABCD1EFGHEFGHsAExsxD.8AE=BF=CG=二次函数一、选择题1y2(x1)23yA.3B.4C.5.12.yX24A.44B.14C.20D.043y=x2+bx+c23y=x2一2x-3bcA.b=2c=2B.b=2c=0C.b=-2c=-1D.b=-3c=2y=-—x2-x+3y=a(x-h)2+k()4=--(x-2)2+2B.y=1(¥-2)2+444y=-3x2一6x+5C.2,3v212y=ax2+bx+cA.B・COA=OC=1()Aab=1Bab=1Cbv2aDacvO4x=0y=141x=2y(03)15.x,yx2+3x+y—3=0,0x+y16y=(x2)(3x)x=17y=ax2+bx+c(a0)xax2+bx+c=0(a0)(50)(20)1P2Py1-x21Px219.y=ax+bx-ca0(-1Dy)1(2Qy)yyy__□2212021y=ax2+bx+cabc>0102b<1ABD11(-2,0),(2,0)111.-1一一X2+一一y222y181011题图13y=ax2+bx+cx=3v22.50.5三、解答题21.⑴c⑵ycx+l122121y-_X2bxc2A20B06xCBA.BCABC260y()x23BM3OA6OAxOOAM32x()7090y()3000100040000)y()x()2y10033)y=ax2+bx1y226y=-x2+2x+mxByC1m2B3Dxyx0y0SABD=SABCDDD1D5CCBCA6D10BABBBD11-12ABDD13y=-2(x-3)2+414.y=(x-2)2-1DDDDDD15.1兀h=5x2=-218DD<6D2DD-\；6D2D1116—4120.—■22221DODO汕xDDDODD1D2cD0ccy21xD1DxDDDDDDb=1無得：O1y=xD1DDDDDDDDDD(1)把直(2,0).B(0,-6)代入尹-2+2^+<7=0二次函数参考答案DDDDDD解得二这个二袂函数的解析式为y=-|x2+4-G4（2）viS抛物线对称轴九直线x=-—=2X-丄）2二点.C的坐标沟(4,0)亠•—OU-Q4二4一2二八S.“厂二—xACOB二丄x2x6=62223DDD(1)0(000)DA(6D0)DM(3D3)D24』1DDDDDDDDDDDy=kx+bDDDDDD25DD1DDDDDx=1DDy=2Dx=2DDy=2+4=6DDDDy=ax2+bxDa+b=2D2DDGD33xD100Dx2Qx叮G=Dx2+32xD100=D(xD16)2+1560x=4DDDD4DDDDDDD3000=70k+b1000=90k+bDDDk=—100,b二10000DDDDDDDDDDDy=-100x+10000D2DDDDDDx-60D(-100x+10000)=40000Dx2一160x+6400=0叮(x一80)2=0nnx=x=8012DDDDD80DDDDDDDDDDDDDDDD40000D4a+2b=6DDDDa=1Db=1DDDy=x2+xDDDD1
