已知抛物线y=ax^2+bx+c(a≠0)

(1)
因该抛物线可由y=-3(x-1)^2得图象向上平移得到
则：a=-3
而：抛物线的顶点(-b/(2a),c-(b^2/(4a^2))
-b/(2a)=1 (因y=-3(x-1)^2顶点x坐标为1)
b=-2a=6

x1+x2=-b/a=1/2
x1x2=c/a=-c/3
x1^2+x2^2=(x1+x2)^2-2x1x2=(1/2)^2+(2/3)c=(1/4)+(2/3)c=26/9
c=95/36
问该抛物线顶点y坐标为:c-(b^2/(4a^2))=(95/36)-1=59/36
而：y=-3(x-1)^2顶点Y坐标为:0
所以：应向上平移59/36

如何由y=ax^2 得到y=ax^2+bx+c的图像？
y=ax^2,顶点坐标为:(0,0)
y=ax^2+bx+c,顶点坐标为:(-b/(2a),c-(b^2/(4a^2))
这就很清楚要怎么移动了

因该抛物线可由y=-3(x-1)^2得图象向上平移得到
则：a=-3
而：抛物线的顶点(-b/(2a),c-(b^2/(4a^2))
-b/(2a)=1 (因y=-3(x-1)^2顶点x坐标为1)
b=-2a=6

x1+x2=-b/a=1/2
x1x2=c/a=-c/3
x1^2+x2^2=(x1+x2)^2-2x1x2=(1/2)^2+(2/3)c=(1/4)+(2/3)c=26/9
c=95/36
问该抛物线顶点y坐标为:c-(b^2/(4a^2))=(95/36)-1=59/36
而：y=-3(x-1)^2顶点Y坐标为:0
所以：应向上平移59/36

如何由y=ax^2 得到y=ax^2+bx+c的图像？
y=ax^2,顶点坐标为:(0,0)
y=ax^2+bx+c,顶点坐标为:(-b/(2a),c-(b^2/(4a^2))