The problem is:a,b,c are edges of triangle,
prove that the equation: ax^2+2(b+c)x+a=0 . has two distinct real root
and my answer is:
a,b,c are edges therefore they are absolute values.
so
a>0
b>0
c>0
also
Δ=4(b+c)^2-4a^2
and I need to prove that Δ>0
so
4(b+c)^2-4a^2>0
which led me for...