Մաթեմատիկա 11.09.24

1. (x + 1)/(x – 3) > 0

    (x + 1)(x – 3) = 
    ⌈x + 1 = 0 ⇒ x = -1

    ⌊x – 3 = 0 ⇒ x = 3

    (x + 1)(x – 3) > 0
    x ∈ (-∞; -1) ∪ (3; +∞)

    x – 3 ≠ 0 ⇒ x ≠ 3

    Պատ․ x ∈ (-∞; -1) ∪ (3; +∞)


    2. (2x – 6)/(x + 4) ≤ 0

    (2x – 6)(x + 4) = 0
    ⌈2x – 6 = 0 ⇒ x = 3
    ⌊x + 4 = 0 ⇒ x = -4

    (2x – 6)(x + 4) ≤ 0
    x ∈ [-4; 3]

    x + 4 ≠ 0 ⇒ x ≠ -4

    Պատ․ x ∈ (-4; 3]


    3. ((x + 4)(3x – 6))/(2x + 10) > 0

    (x + 4)(3x – 6)(2x + 10) = 0
    ⌈x + 4 = 0 ⇒ x = -4
    |3x – 6 = 0 ⇒ x = 2
    ⌊2x + 10 = 0 ⇒ x = -5

    (x + 4)(3x – 6)(2x + 10) > 0
    x ∈ (-5; -4) ∪ (2; +∞)

    2x + 10 ≠ 0 ⇒ x ≠ -5

    Պատ․ x ∈ (-5; -4) ∪ (2; +∞)


    4. (x – 3)/((2x – 4)(x + 5)) ≥ 0

    (x – 3)(2x – 4)(x + 5) = 0
    ⌈x – 3 = 0 ⇒ x = 3
    |2x – 4 = 0 ⇒ x = 2
    ⌊x + 5 = 0 ⇒ x = -5

    (x – 3)(2x – 4)(x + 5) ≥ 0
    x ∈ [-5; 2] ∪ [3; +∞)

    2x – 4 ≠ 0 ⇒ x ≠ 2
    x + 5 ≠ 0 ⇒ x ≠ -5

    Պատ․ x ∈ (-5; 2) ∪ [3; +∞)


    5.(x(x + 5))/((2x + 6)(x – 7)) ≥ 0

    x(x + 5)(2x + 6)(x – 7) = 0
    ⌈x = 0
    |x + 5 = 0 ⇒ x = -5
    |2x + 6 = 0 ⇒ x = -3
    ⌊x – 7 = 0 ⇒ x = 7

    x(x + 5)(2x + 6)(x – 7) ≥ 0
    x ∈ (-∞; -5] ∪ [-3; 0] ∪ [7; +∞)

    ⌈2x + 6 ≠ 0 ⇒ x ≠ -3
    ⌊x – 7 ≠ 0 ⇒ x ≠ 7

    Պատ․ x ∈ (-∞; -5] ∪ (-3; 0] ∪ (7; +∞)