a=1
b=-(m-3)
c=m-3
Δ= [-(m-3)]²-4·1(m-3)=m²-6m+9-4m+12=m²-10m+21
Δ=m²-10m+21
egalezi Δ cu 0.
m²-10m+21=0
a=1
b=-10
c=21
Δ=100-4·21=100-84=16
m1=[tex] \frac{10+4}{2} [/tex]=7
m2=[tex] \frac{10-4}{2} [/tex]=3.
faci tabel de semne: m,-inf,3,7,+inf
sub m pui m²-10m+21
se anuleaza in 3 si 7(pui 0 sub ele)
intre radacini ai ---------- , iar in rest ai +++++++.
m∈(-inf, 3) reunit cu (7,+inf)
