(x-4)²-5≥0
x²-8x+16-5≥0
x²-8x+11≥0
egalam cu 0.
a=1
b=-8
c=11
Δ=64-44
Δ=20
x1=[tex] \frac{8+2 \sqrt{5} }{2} [/tex]=[tex] \frac{2(4+ \sqrt{5)} }{2} [/tex]=4+√5.
x2=4-√5
facem tabel de semne
x | -inf 4-√5 4+√5 +inf
x²-8x+11 |+++++++++0-------------0++++++++
solutie finala: x∈(-inf; 4-√5] reunit cu [4+√5; +inf)
