a) y=x²-9x+14 Δ=b²-4ac Δ=81-56=25 √Δ=5 x₁=-b-√Δ/2a x₂=-b+√Δ/2a x₁=9-5/2=2 x₂=9+5/2=7 y=a(x-x₁)(x-x₂) <- postac iloczynowa y=(x-2)(x-7) b) y=x²-11x+18 Δ=121-72=49 √Δ=7 x₁=11-7/2=2 x₂=11+7/2=9 y=(x-2)(x-9) c) y=x²-5x-14 Δ=25+56=81 √Δ=9 x₁=5-9/2=-2 x₂=5+9/2=7 y=(x+2)(x-7) d) y=-x²+8x+33 Δ=64+132=196 √Δ=14 x₁=-8-14/-2=-11 x₂=-8+14/-2=-3 y=-1(x+11)(x+3) e) y=2x²+x-1 Δ=1+8=9 √Δ=3 x₁=-1-3/4=-1 x₂=-1+3/4=½ y=2(x+1)(x-½) f) y=-2x²+5x+3 Δ=25+24=49 √Δ=7 x₁=-5-7/-4=3 x₂=-5+7/-4=-½ y=-2(x-3)(x+½) g) y=-3x²-13x+10 Δ=169+120=289 √Δ=17 x₁=13-17/-6=⅔ x₂=13+17/-6=-5 y=-3(x-⅔)(x+5) h) y=3x²-x-4 Δ=1+48=49 √Δ=7 x₁=1-7/6=-1 x₂=1+7/6=1⅓ y=3(x+1)(x-1⅓) i) y=-6x²+x+2 Δ=1+48=49 √Δ=7 x₁=-1-7/-12=⅔ x₂=-1+7/-12=-½ y=-6(x-⅔)(x+½) j) y=8x²+6x-9 Δ=36+288=324 √Δ=18 x₁=-6-18/16=-1½ x₂=-6+18/16=¾ y=8(x+1½)(x-¾) k) y=-10x²+37-7 Δ=1369-280=1089 √Δ=33 x₁=-37-33/-20=3½ x₂=-37+33/-20=⅕ y=-10(x-3½)(x-⅕)
