Հանրահաշիվ 08.11.23

110-ա,գ. Լուծեք անհավասարումը․

ա) x2 – 3 > 0

x2 – 3 = 0
(x – √3)(x + √3) = 0

⌈x – √3 = 0
⌊x + √3 = 0

⌈x = √3
⌊x = -√3 

x2 – 3 > 0

x ∈ (-∞; -√3) ∪ (√3; +∞)

գ) 2 – x2 < 0

2 – x2 = 0
(√2 – x)(√2 + x) = 0

⌈√2 – x = 0
⌊√2 + x = 0

⌈-x = √2
⌊x = √2

[x = -√2

2 – x2 < 0

x ∈ (-√2; √2)


ՏՆԱՅԻՆ․


110-բ,դ. Լուծեք անհավասարումը․

բ) x2 – 5 < 0

x2 – 5 = 0
(x – √5)(x + √5) = 0

⌈x – √5 = 0
⌊x + √5 = 0

⌈x = √5
⌊x = -√5 

x2 – 5 < 0

x ∈ (-√5; √5)

դ) 13 – x2 > 0

13 – x2 = 0
(√13 – x)(√13 + x) = 0

⌈√13 – x = 0
⌊√13 + x = 0

⌈-x = √13
⌊x = √13

⌈x = -√13
⌊x = √13

13 – x2 > 0

x ∈ (-∞; -√13) ∪ (√13; +∞)


111-բ,դ. Լուծեք անհավասարումը․

բ) 1,3x2 – 2x < 0

1,3x2 – 2x = 0
x(1,3x – 2) = 0

⌈x = 0
⌊1,3x – 2 = 0

⌈x = 0
⌊1,3x = 2

⌈x = 0
⌊x = 20/13

1,3x2 – 2x < 0

x ∈ (0; 20/13)

դ) 7/8x2 – 1 3/5 > 0

7/8x28/5 = 0
(√7/8x – √8/5)(√7/8x + √8/5) = 0

⌈√7/8x – √8/5 = 0
⌊√7/8x + √8/5 = 0

⌈√7/8x = √8/5
⌊√7/8x = -√8/5

⌈x = √8/5 : 7/√8 = √8/5 * √8/7 = 8/35
⌊x = –√8/5 : 7/√8 = –√8/5 * √8/7 = –8/35

7/8x2 – 1 3/5 > 0

x ∈ (-∞; –8/35) ∪ (8/35; +∞)


113-բ,դ,զ. Լուծեք անհավասարումը․

բ) x2 + 4x + 3 < 0

x2 + 4x + 3 = 0
a = 1
b = 4
c = 3

D = b2 – 4ac = 16 – 4 * 1 * 3 = 16 – 12 = 4

x = -b + √D/2a = -4 + √4/2 * 1 = -4 + 2/2
x1 = -4 + 2/2 = -2/2 = -1
x2 = -4 – 2/2 = -6/2 = -3

x2 + 4x + 3 < 0

x ∈ (-3; -1)

դ) x2 – 5x + 4 > 0

x2 – 5x + 4 = 0
a = 1
b = -5
c = 4

D = b2 – 4ac = 25 – 4 * 1 * 4 = 25 – 16 = 9

x = -b + √D/2a = 5 + √9/2 * 1 = 5 + 3/2
x1 = 5 + 3/2 = 8/2 = 4
x2 = 5 – 3/2 = 2/2 = 1

x2 – 5x + 4 > 0

x ∈ (-∞; 1) ∪ (4; +∞)

զ) 4x2 – x – 3 < 0

4x2 – x – 3 = 0
a = 4
b = -1
c = -3

D = b2 – 4ac = 1 – 4 * 4 * -3 = 1 + 48 = 49

x = -b + √D/2a = 1 + √49/2 * 4 = 1 + 7/8
x1 = 1 + 7/8 = 8/8 = 1
x2 = 1 – 7/8 = -6/8 = –3/4

4x2 – x – 3 < 0

x ∈ (-3/4; 1)


114-բ,դ,զ. Լուծեք անհավասարումը․

բ) 0,5x2 + 88x + 24 < 0

0,5x2 + 88x + 24 = 0
a = 0,5
b = 88
c = 24

D = b2 – 4ac = 7744 – 4 * 24 * 0,5 = 7696

x = -b + √D/2a = -88 + √7696/2 * 0,5 = -88 + 16√481
x1 = -88 + 4√481 ≈ -0,27315
x2 = -88 – 4√481 ≈ -175,72685

0,5x2 + 88x + 24 < 0

x ∈ (-175,72685; -0,27315)

դ) 4x + 1/4x2 + 12 > 0

1/4x2 + 4x + 12 = 0
a = 0,25
b = 4
c = 12

D = b2 – 4ac = 16 – 4 * 0,25 * 12 = 16 – 12 = 4

x = -b + √D/2a = -4 + √4/2 * 0,25 = -4 + 2/0,5
x1 = -4 + 2/0,5 = -2/0,5 = -4
x2 = -4 – 2/0,5 = -6/0,5 = -12

1/4x2 + 4x + 12 > 0

x ∈ (-∞; -12) ∪ (-4; +∞)

զ) 8x2 – 3 – 2x > 0

8x2 – 2x – 3 = 0
a = 8
b = -2
c = -3

D = b2 – 4ac = 4 – 4 * 8 * -3 = 4 + 96 = 100

x = -b + √D/2a = 2 + √100/2 * 8 = 2 + 10/16
x1 = 2 + 10/16 = 12/16 = 3/4
x2 = 2 – 10/16 = -8/16 = –1/2

8x2 – 3 – 2x > 0

x ∈ (-∞; –1/2) ∪ (3/4; +∞)