f(x)∩Ox=∅
ecuatia axei Ox este y=0
adica f(x) =0 sa NU AIBE SOLUTII REALE
deci Δ<0
(-2(m-1))²-4m(m+1)<0
4(m-1)²-4m²-4m<0
(m-1)²-m²-m<0
m²-2m+1-m²-m<0
1-3m<0
3m-1>0
m>1/3⇔m∈(1/3;∞)
b) pt m>0 Im f=[-Δ/4a;∞)
pt m<0, Im f=(-∞;-Δ/4a]
unde -Δ/4a=4(3m-1)/4m=(3m-1)/m
c) -b/2a=2
2(m-1)/2m=2
(m-1)/m=2
m-1=2m
-1=2m-m=m
m=-1