Question

用配方法将二次函数y=ax2-bx+c化成y=a(x-h)2+k的形式 亲注意是"-bx"

Answer 1

y=ax2-bx+c

=a(x²-bx/a)+c

=a(x²-bx/a+b²/4a²)+c-b²/4a

=a(x-b/2a)²+(4ac-b²﹚／4a