Question

ax2+bx+c=0配方法怎么做？

Answer 1

Answer 2

a[x²+x*b/a+(b/2a)²]-b²/4a+c=0
a(x+b/2a)²=b²/4a-c
(x+b/2a)²=(b²-4ac)/4a²
x+b/2a=±√[(b²-4ac)/4a²]
=±√(b²-4ac)/2a
x=-b/2a±√(b²-4ac)/2a=(-b±√(b²-4ac)/2a

Answer 3

x2+b/ax+c/a=0
x2+b/ax+b2/4a2x2=-c+b2/4a2x2
(x+b/2ax)2=-c+b2/4a2x2
2皆为平方

Answer 4

x^2+(b/a)x+c/a=0
x^2+(b/a)x+(b/2a)^2+c/a-(b/2a)^2=0
(x+b/2a)^2=(b^2-4ac)/4a^2
x+b/2a=±√(b^2-4ac)/2a
x=[-b±√(b^2-4ac)]/2a

Answer 5

b的1/2的平方