解方程:ax^+bx+c=0

a乘x的平方+bx+c=0
x^2+(b/a)x+c/a=0
x^2+(b/a)x=-c/a
x^2+(b/a)x+b^2/4a^2=-c/a+b^2/4a^2
x^2+(b/a)x+b^2/4a^2=(b^2-4ac)/4a^2
(x+b/2a)^2=(b^2-4ac)/4a^2
x+b/2a=±√(b^2-4ac)/2a
x=[-b±√(b^2-4ac)]/2a
x^2+(b/a)x+c/a=0
x^2+(b/a)x=-c/a
x^2+(b/a)x+b^2/4a^2=-c/a+b^2/4a^2
x^2+(b/a)x+b^2/4a^2=(b^2-4ac)/4a^2
(x+b/2a)^2=(b^2-4ac)/4a^2
x+b/2a=±√(b^2-4ac)/2a
x=[-b±√(b^2-4ac)]/2a (b^2-4ac>0)
还有无解的情况：b^2-4ac<0
一个解的情况:b^2-4ac=0
x=-b/2a
x^2+(b/a)x+c/a=0
x^2+(b/a)x=-c/a
配方：x^2+(b/a)x+b^2/4a^2=-c/a+b^2/4a^2
x^2+(b/a)x+b^2/4a^2=(b^2-4ac)/4a^2
(x+b/2a)^2=(b^2-4ac)/4a^2
x+b/2a=±√(b^2-4ac)/2a
x=[-b±√(b^2-4ac)]/2a (b^2-4ac>0)
无实数根：b^2-4ac<0
一个解的情况:b^2-4ac=0
x=-b/2a

a乘x的平方+bx+c=0
x^2+(b/a)x+c/a=0
x^2+(b/a)x=-c/a
x^2+(b/a)x+b^2/4a^2=-c/a+b^2/4a^2
x^2+(b/a)x+b^2/4a^2=(b^2-4ac)/4a^2
(x+b/2a)^2=(b^2-4ac)/4a^2
x+b/2a=±√(