Question

二次三项式ax^2+bx+c,配方法

Answer 1

ax^2+bx+c

=a(x^2+bx/a)+c

=a(x^2+2*b/2a*x+(b/2a)^2-(b/2a)^2)+c

=a(x+b/2a)^2-a*(b/2a)^2+c

=a(x+b/2a)^2+(4ac-b^2)/4a