一元二次方程根与系数的关系(韦达定理)急急急急急!!!!!!!

ax^2+bx+c=0

(1)两根互为倒数的条件是:
x1*x2=1,c/a=1,a=c

(2)两根互为相反数的条件是:
x1+x2=0,-b/a=0,b=0

(3)两根异号的条件是:
x1*x2<0
c/a<0

(4)两根同号的条件是:
x1*x2>0
c/a>0

(5)两根都是正数的条件是:
x1*x2>0,x1+x2>0
c/a>0,-b/a>0

(6)两根负数的条件是:
x1*x2>0,x1+x2<0
c/a>0,-b/a<0

假设方程是x^2+bx+c=0
1 c=1
2 b=0
3 c＜0
4 c＞0
5 -b＞0 c＞0
6 -b＜0 c＜0