-12x²-x+1<0 x³+x²-9x-9=0

-12x²-x+1<0 Δ=1+48=49 x₁=1/4 x₂=-1/3 xnalezy (-1/3,1/4) x³+x²-9x-9=0 x²(x+1)-9(x+1)=0 (x²-9)(x+1)=0 x=3 v x=-3 v x=-1