ax2+bx+c=0
x2+bax+ca=0
x2+bax=−ca
x2+bax+b2a2=b2a2−ca
x+b2a2=b2a2−ca
x+b2a2=b24a2−ca
x+b2a2=b24a2−4a4aca
x+b2a2=b24a2−4ac4a2
x+b2a2=b2−4ac4a2
x+b2a=
±
b2−4ac4a2
x+b2a=
±
b2−4ac4a2
x+b2a=
±
b2−4ac2a
x=
±
b2−4ac2a−b2a
x=
±
−bb2−4ac2a
a
x
2
b
x
c
0
x
2
b
a
x
c
a
0
x
2
b
a
x
c
a
x
2
b
a
x
b
2
a
2
b
2
a
2
c
a
x
b
2
a
2
b
2
a
2
c
a
x
b
2
a
2
b
2
4
a
2
c
a
x
b
2
a
2
b
2
4
a
2
4
a
4
a
c
a
x
b
2
a
2
b
2
4
a
2
4
a
c
4
a
2
x
b
2
a
2
b
2
4
a
c
4
a
2
x
b
2
a
±
b
2
4
a
c
4
a
2
x
b
2
a
±
b
2
4
a
c
4
a
2
x
b
2
a
±
b
2
4
a
c
2
a
x
±
b
2
4
a
c
2
a
b
2
a
x
±
b
b
2
4
a
c
2
a
(1)
x=-b±b2-4ac2ax=-b±b2-4ac2a
(2)