rozwiaz nierownosci:
a) 2x do kwadratu -6x>0
b)-xdo kwadratu +2x-1 > lub = 0
c)-3xkwadrat+2x-1<0
rozwiaz rownanie
3x do trzeciej +3x do drugiej-2x=0
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a)![2x^2-6x>0\\ \Delta = b^{2}-4ac=36-4*2*2=36-0=36\\ x_{1}=\frac {-b-\sqrt {\Delta}}{2a}=\frac {6-6}{4}=0\\ x_{2}=\frac {-b+\sqrt {\Delta}}{2a}=\frac {6+6}{4}=3\\ \\ a = 2 > 0\\ \\ x \in (-\infty; \ 0) \cup (3; \ +\infty) 2x^2-6x>0\\ \Delta = b^{2}-4ac=36-4*2*2=36-0=36\\ x_{1}=\frac {-b-\sqrt {\Delta}}{2a}=\frac {6-6}{4}=0\\ x_{2}=\frac {-b+\sqrt {\Delta}}{2a}=\frac {6+6}{4}=3\\ \\ a = 2 > 0\\ \\ x \in (-\infty; \ 0) \cup (3; \ +\infty)](https://tex.z-dn.net/?f=2x%5E2-6x%3E0%5C%5C+%5CDelta+%3D+b%5E%7B2%7D-4ac%3D36-4%2A2%2A2%3D36-0%3D36%5C%5C+x_%7B1%7D%3D%5Cfrac+%7B-b-%5Csqrt+%7B%5CDelta%7D%7D%7B2a%7D%3D%5Cfrac+%7B6-6%7D%7B4%7D%3D0%5C%5C+x_%7B2%7D%3D%5Cfrac+%7B-b%2B%5Csqrt+%7B%5CDelta%7D%7D%7B2a%7D%3D%5Cfrac+%7B6%2B6%7D%7B4%7D%3D3%5C%5C+%5C%5C+a+%3D+2+%3E+0%5C%5C+%5C%5C+x+%5Cin+%28-%5Cinfty%3B+%5C+0%29+%5Ccup+%283%3B+%5C+%2B%5Cinfty%29)
b)![-x^2+2x-1\geq0\\ \Delta = b^{2}-4ac=4-4*(-1)*(-1)=4-4=0\\ x_0=\frac {-b}{2a}=\frac {-2}{-2}=1\\ \\ a = - 1 < 0\\ \\ -x^2+2x-1\geq0\\ \Delta = b^{2}-4ac=4-4*(-1)*(-1)=4-4=0\\ x_0=\frac {-b}{2a}=\frac {-2}{-2}=1\\ \\ a = - 1 < 0\\ \\](https://tex.z-dn.net/?f=-x%5E2%2B2x-1%5Cgeq0%5C%5C+%5CDelta+%3D+b%5E%7B2%7D-4ac%3D4-4%2A%28-1%29%2A%28-1%29%3D4-4%3D0%5C%5C+x_0%3D%5Cfrac+%7B-b%7D%7B2a%7D%3D%5Cfrac+%7B-2%7D%7B-2%7D%3D1%5C%5C+%5C%5C+a+%3D+-+1+%3C+0%5C%5C+%5C%5C+)
wartości są większe lub równe zero dla x = 1
c)![-3x^2+2x-1<0\\ \Delta = b^{2}-4ac=4-4*(-3)*(-1)=4-12=-8\\ \\ a = - 3 < 0\ i\ \Delta = - 8 < 0\\ \\ x \in R -3x^2+2x-1<0\\ \Delta = b^{2}-4ac=4-4*(-3)*(-1)=4-12=-8\\ \\ a = - 3 < 0\ i\ \Delta = - 8 < 0\\ \\ x \in R](https://tex.z-dn.net/?f=-3x%5E2%2B2x-1%3C0%5C%5C+%5CDelta+%3D+b%5E%7B2%7D-4ac%3D4-4%2A%28-3%29%2A%28-1%29%3D4-12%3D-8%5C%5C+%5C%5C+a+%3D+-+3+%3C+0%5C+i%5C+%5CDelta+%3D+-+8+%3C+0%5C%5C+%5C%5C+x+%5Cin+R+)
a)![3x^3+3x^2-2x = 0\\ x(3x^2+3x-2) = 0\\ x = 0 \ lub \ 3x^2+3x-2 = 0 \\\\ x = 0 \\\\ 3x^2+3x-2 = 0\\ \Delta = b^{2}-4ac=9-4*3*(-2)=9+24=33\\ x_{1}=\frac {-b-\sqrt {\Delta}}{2a}=\frac {3-\sqrt {33}}{6} \\ x_{2}=\frac {-b+\sqrt {\Delta}}{2a}=\frac {-3+\sqrt {33}}{6} 3x^3+3x^2-2x = 0\\ x(3x^2+3x-2) = 0\\ x = 0 \ lub \ 3x^2+3x-2 = 0 \\\\ x = 0 \\\\ 3x^2+3x-2 = 0\\ \Delta = b^{2}-4ac=9-4*3*(-2)=9+24=33\\ x_{1}=\frac {-b-\sqrt {\Delta}}{2a}=\frac {3-\sqrt {33}}{6} \\ x_{2}=\frac {-b+\sqrt {\Delta}}{2a}=\frac {-3+\sqrt {33}}{6}](https://tex.z-dn.net/?f=3x%5E3%2B3x%5E2-2x+%3D+0%5C%5C+x%283x%5E2%2B3x-2%29+%3D+0%5C%5C+x+%3D+0+%5C+lub+%5C+3x%5E2%2B3x-2+%3D+0+%5C%5C%5C%5C+x+%3D+0+%5C%5C%5C%5C+3x%5E2%2B3x-2+%3D+0%5C%5C+%5CDelta+%3D+b%5E%7B2%7D-4ac%3D9-4%2A3%2A%28-2%29%3D9%2B24%3D33%5C%5C+x_%7B1%7D%3D%5Cfrac+%7B-b-%5Csqrt+%7B%5CDelta%7D%7D%7B2a%7D%3D%5Cfrac+%7B3-%5Csqrt+%7B33%7D%7D%7B6%7D+%5C%5C+x_%7B2%7D%3D%5Cfrac+%7B-b%2B%5Csqrt+%7B%5CDelta%7D%7D%7B2a%7D%3D%5Cfrac+%7B-3%2B%5Csqrt+%7B33%7D%7D%7B6%7D)
rozwiązaniem są:
a)
2x²-6x > 0
2x(x-3) > 0
x = 0 v x = 3
a = 2 > 0, ramiona paraboli skierowane w górę
x ∈ (-∞;0) u (3;+∞)
b)
-x²+2x-1 ≥ 0
Δ = 4-4 = 0
x = -2/(-2) = 1
x₀ = 1
a = -1 < 0, ramiona paraboli skierowane w dół
Funkcja nie przyjmuje wartosci dodatnich; wartość zero przyjmuje dla argumentu 1.
-x²+2x-1 ≥ 0 ⇔ x = 1
Liczba 1 jest jedynym rozwiazaniem tej nierówności.
c)
-3x²+2x-1 < 0
Δ = 4-12 = -8
a = -3 < 0, ramiona paraboli skierowana w dół, parabola nie przecina osi OX
x = R
d)
3x³+3x²-2x = 0
x(3x²+3x-2) = 0
x = 0
lub
3x²+3x-2 = 0
Δ = 9+24 = 33
√Δ = √33
x1 = (-3-√33)/6
x2 = (-3+√33)/6
Odp. x = (-3-√33)/6 v x = 0 v x = (-3+√33)/6