69.   y = x² + x – 6 funksiyaning grafigini yasang. Grafik bo`yicha x ning funksiya musbat qiymatlar; manfiy qiymatlar qabul qiladigan qiymatlarini toping.

 

70.   (Og`zaki.) y = ax<sup>2</sup> + bx + c funksiya grafigidan foydalanib (21- rasm), x ning qanday qiymatlarida bu funksiya musbat qiymatlar, manfiy qiymatlar, nolga teng qiymat qabul qilishini ko`rsating.

 

      Kvadrat tengsizlikni yeching (71 – 75):

 

71.   1) x² – 3x + 2 ≤ 0;                            2) x² – 3x – 4 ≥ 0;

3) –x² + 3x – 2 < 0;                          4) –x² + 3x + 2 > 0.

 

72.   1) 2x² + 7x – 4 < 0;                          2) 3x² – 5x – 2 > 0;

3) –2x² + x + 1 ≥ 0;                         4) –4x² + 3x + 1 ≤ 0.

 

73.   1) x² – 6x + 9 > 0;                            2) x² – 14x + 49 ≤ 0;

3) 4x² – 4x + 1 ≥ 0;                          4) 4x² – 20x + 25 ≤ 0;

5) –9x² – 6x – 1 < 0;                        6) –2x² + 6x + 4,5 ≤ 0.

 

74.   1) x² – 4x + 6 > 0;                            2) x² + 6x + 10 < 0;

3) x² + x + 2 > 0;                              4) x² + 3x + 5 < 0;

5) 2x² – 3x + 7 < 0;                          6) 4x² – 8x + 9 > 0.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

75.   1) 5 – x² ≥ 0;                                    2) –x² + 7 < 0;

3) –2,1x² + 10,5x < 0;                      4) –3,6x² – 7,2x < 0;

5) –6x² – x + 12 > 0;                        6) –3x² – 6x + 45 < 0;

7) –x² + 4,5x – 4 > 0;                    8) –x² – 3x – 2 > 0.

 

76.   (Og`zaki.) Tengsizlikni yeching:

1) x² + 10 > 0;                                 2) x² + 9 < 0;

3) (x – 1)² + 1 > 0;                           4) (x + 5)² + 3 < 0;

5) –(x + 1)² – 2 < 0;                         6) –(x – 2)² – 4 > 0;

7) 0,5x² + 8 ≤ 0;                               8) .

        Kvadart tengsizlikni yeching (77 – 79):

 

77.   1) 4x² – 9 > 0;                                  2) 9x² – 25 > 0;

3) x² – 3x + 2 > 0;                            4) x² – 3x – 4 < 0;

5) 2x² – 4x + 9 ≤ 0;                          6) 3x² + 2x + 4 ≥ 0;

7)  x² – 4x ≥ –8;                            8) x² + 2x ≤ –3.

 

 

78.   1) 2x² – 8x ≤ –8;                              2) x² + 12x ≥ –36;

3) 9x² + 25 < 30x;                            4) 16x² + 1 > 8x;

5) 2x² – x ≥ 0;                                  6) 3x + x ≤ 0;

7) 0,4x² – 1,1x + 1 ≥ 0;                     8) x² – x + 0,26 ≤ 0.

 

79.   1) x(x + 1) < 2(1 – 2x – x²);             2) x² + 2 < 3x – x²;

3) 6x² + 1 ≤ 5x – x²;                    4) 2x(x – 1)< 3(x + 1);

5) x –  ≤ x + 1;                          6) x² +  ≥ x – 1.

 

80.   x ning funksiya noldan katta bo`lmagan qiymatlarni qabul qiladigan barcha qiymatlarini toping:

1) y = –x² + 6x – 9;                          2) y = x² – 2x + 1;

3) ;                      4) .

 

81.   1) x² – 2x + q > 0 tengsizlikning q > 1 bo`lgandagi yechimlari x ning barcha haqiqiy qiymatlari bo`lishini ko`rsating;

2) x² + 2x + q ≤ 0 tengsizlik q > 1 bo`lganda haqiqiy yechimlarga ega emasligini ko`rsating.

 

82.   r ning

x² – (2 + r)x + 4 > 0

      tengsizlik x ning barcha haqiqiy qiymatlaridi bajariladigan barcha qiymatlarini toping.

 

 

TEST