已知二次函数f（x）图像的顶点是m（-1.5,49）所以f（x）=a(x+1.5)^2+49=ax^2+3ax+9\4a+49所以x1+x2=-b\a=-3x1x2=c\a=(9a+196)\4a又(x1-x2)^2=(x1+x2)^2-4x1x2=196\a所以：x1-x2=14根号a\a=7所以a1=4,a2=0(舍）所以f...