Question

二次函数y=ax^2+bx+c怎样配方?

Answer 1

y=ax^2+bx+c

y=a[x^2+2{b/(2a)}x]+c

y=a[x^2+2{b/(2a)}x+(b/2a)^2]+c-b^2/(4a)

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