Question

׳⁻≥81×
×⁴⁺2׳⁻×⁻2<0
⁻׳⁺7×⁻3×⁺21≥0
2×(×⁺2) (×⁻3)<0
(8⁻×) (×⁻3) (2⁻×) (×⁻1)≤0
ײ (×⁺1)²(×⁻3) (½⁻×)>0

Answer 1

׳⁻≥81×
x³-81x≥0
x(x²-81)≥0
x(x-√81)(x+√81)≥0
x=0, x=+-√81

rozwiązanie x∈(-∞,-√81>u<0,√81>

×⁴⁺2׳⁻×⁻2<0
x³(x+2)-(x+2)<0
(x+2)(x³-1)<0
x=-2, x=1
Odp.x∈(-2,1)

⁻׳⁺7ײ⁻3×⁺21≥0
-x²(x-7)-3(x-7)≥0
(x-7)(x²-3)≥0
(x-7)(x-√3)(x+√3)≥0
x=7, x=+-√3
odp. x∈(-∞,-√3>u<√3,7>

2×(×⁺2) (×⁻3)<0
x=0,x=-2, x=3
odp. x∈(-2,0)u(3,+∞)

(8⁻×) (×⁻3) (2⁻×) (×⁻1)≤0
x=8 , x=3, x=2, x=1
Odp. x∈<1,2>u<3,8>

ײ (×⁺1)²(×⁻3) (½⁻×)>0
x=0 , x=-1, x=3, x=1/2
odp. x∈(-∞,-1)u(0,1/2)u(3,∞)

gdzie u - suma zbiorów