对称轴是直线x=3,则二次函数可表达为y = a(x-3)² + b
代入A(3,-2):-2 = a(3-3)² + b,b = -2
y = a(x-3)² -2
代入B(1,0):0 = a(1-3)² -2
4a = 2
a = 1/2
y = (1/2)(x-3)² -2
= x² -3x + 5/2
对称轴是直线x=3,则二次函数可表达为y = a(x-3)² + b
代入A(3,-2):-2 = a(3-3)² + b,b = -2
y = a(x-3)² -2
代入B(1,0):0 = a(1-3)² -2
4a = 2
a = 1/2
y = (1/2)(x-3)² -2
= x² -3x + 5/2