632. Լուծեք հավասարումը.
ա) x² − 6x + 8 = 0
D = b2 − 4ac = 36 – 32 = 4
x1 = (-b + √D)/2a = (6 + 2)/2 = 4
x2 = (-b – √D)/2a = (6 – 2)/2 = 2
բ) x² − 2x − 15 = 0
D = b2 − 4ac = 4 + 60 = 64
x1 = (-b + √D)/2a = (2 + 8)/2 = 5
x2 = (-b – √D)/2a = (2 – 8)/2 = -3
գ) x² + 6x + 8 = 0
D = b2 − 4ac = 36 – 32 = 4
x1 = (-b + √D)/2a = (-6 + 2)/2 = -2
x2 = (-b – √D)/2a = (-6 – 2)/2 = -4
դ) x² + 2x − 15 = 0
D = b2 − 4ac = 4 + 60 = 64
x1 = (-b + √D)/2a = (-2 + 8)/2 = 3
x2 = (-b – √D)/2a = (-2 – 8)/2 = -5
ե) x² + 20x + 51 = 0
D = b2 − 4ac = 400 – 204 = 196
x1 = (-b + √D)/2a = (-20 + 14)/2 = -3
x2 = (-b – √D)/2a = (-20 – 14)/2 = 17
զ) x² − 22x − 23 = 0
D = b2 − 4ac = 484 + 92 = 576
x1 = (-b + √D)/2a = (22 + 24)/2 = 23
x2 = (-b – √D)/2a = (22 – 24)/2 = -1
է) x² − 20x + 69 = 0
D = b2 − 4ac = 400 – 276 = 124
x1 = (-b + √D)/2a = (20 + √124)/2 = 15,5
x2 = (-b – √D)/2a = (20 – √124)/2 = 4,4
ը) x² + 22x + 21 = 0
D = b2 − 4ac = 484 – 84 = 400
x1 = (-b + √D)/2a = (-22 + 20)/2 = -1
x2 = (-b – √D)/2a = (-22 – 20)/2 = -21
633. Լուծեք հավասարումը.
ա) x² − 4x + 4 = 0
D = b2 − 4ac = 16 – 16 = 0
x1,2 = (-b + √D)/2a = (4 ± 0)/2 = 2
բ) x² − 8x + 20 = 0
D = b2 − 4ac = 64 – 80 = -16
Արամտ չկա
գ) x² − 5/2x + 1 = 0
D = b2 − 4ac = 25/4 – 4 = 2,25
x1 = (-b + √D)/2a = (2,5 + 1,5)/2 = 2
x2 = (-b – √D)/2a = (2,5 – 1,5)/2 = 0,5
դ) x² + 10/3x + 1 = 0
D = b2 − 4ac = 100/9 – 4 = 7,(1)
x1 = (-b + √D)/2a = (-3,(3) + √7,(1))/2 = -0,3
x2 = (-b – √D)/2a = (-3,(3) – √7,(1))/2 = -3
ե) x² + 16x + 48 = 0
D = b2 − 4ac = 256 – 192 = 64
x1 = (-b + √D)/2a = (-16 + 8)/2 = -4
x2 = (-b – √D)/2a = (-16 – 8)/2 = -12
զ) x² − 9x − 22 = 0
D = b2 − 4ac = 81 + 88 = 169
x1 = (-b + √D)/2a = (9 + 13)/2 = 11
x2 = (-b – √D)/2a = (9 – 13)/2 = -2
է) x² + 8x + 71 = 0
D = b2 − 4ac = 64 – 284 = -220
Արմատ չկա
ը) x² + 12x + 40 = 0
D = b2 − 4ac = 144 – 160 = -16
Արմատ չկա
634. Լուծեք հավասարումը.
ա) x² − x − 2 = 2
x² − x − 4 = 0
D = b2 − 4ac = 1 + 16 = 17
x1 = (-b + √D)/2a = (1 + √17)/2 = 2,5
x2 = (-b – √D)/2a = (1 – √17)/2 = -1,5
բ) x² − 5x − 24 = 0
D = b2 − 4ac = 25 + 96 = 121
x1 = (-b + √D)/2a = (5 + 11)/2 = 8
x2 = (-b – √D)/2a = (5 – 11)/2 = -3
գ) x² − 3x + 2 = 0
D = b2 − 4ac = 9 – 8 = 1
x1 = (-b + √D)/2a = (3 + 1)/2 = 2
x2 = (-b – √D)/2a = (3 – 1)/2 = 1
դ) x² − 13x + 42 = 0
D = b2 − 4ac = 169 – 168 = 1
x1 = (-b + √D)/2a = (13 + 1)/2 = 7
x2 = (-b – √D)/2a = (13 – 1)/2 = 6
ե) x² + x − 2 = 0
D = b2 − 4ac = 1 + 8 = 9
x1 = (-b + √D)/2a = (-1 + 3)/2 = 1
x2 = (-b – √D)/2a = (-1 – 3)/2 = -2
զ) x² − x − 6 = 0
D = b2 − 4ac = 1 + 24 = 25
x1 = (-b + √D)/2a = (1 + 5)/2 = 3
x2 = (-b – √D)/2a = (1 – 5)/2 = 2
է) x² + 14x + 48 = 0
D = b2 − 4ac = 196 – 192 = 4
x1 = (-b + √D)/2a = (-14 + 2)/2 = -6
x2 = (-b – √D)/2a = (-14 – 2)/2 = -8
ը) x² + 17x + 66 = 0
D = b2 − 4ac = 289 – 264 = 25
x1 = (-b + √D)/2a = (-17 + 5)/2 = -6
x2 = (-b – √D)/2a = (-17 – 5)/2 = -11