1)Հաշվեք քառակուսային եռանդամի տարբերիչը.
ա)2x2 + 5x — 3
D = b2 — 4ac
D = 52 — 4(2 * (-3))
D = 25 + 24 = 49
D > 0
բ)x2 + 6x + 9
D = b2 — 4ac
D = 62 — 4(1 * 9)
D = 36 — 36 = 0
D = 0
գ)x2 + 2x + 2
D = b2 — 4ac
D = 22 — 4(1 * 2)
D = 4 — 8 = -4
D < 0
դ)2x2 — 5x — 7
D = b2 — 4ac
D = 52 — 4(2 * (-7))
D = 25 + 56 = 81
D > 0
ե)6x2 + x — 2
D = b2 — 4ac
D = 12 — 4(6 * (-2))
D = 1 + 48 = 49
D > 0
զ)3x2 + 4x + 5
D = b2 — 4ac
D = 42 — 4(3 * 5)
D = 16 — 60 = 44
D > 0
2)Լուծե՛ք քառակուսային հավասարումը.
ա)2y2 — 9y + 10 = 0
D = b2 — 4ac
D = 92 — 4(2 * 10)
D = 81 — 80 = 1
D > 0
x = (-b) ± √D / 2a
x1 = (-9) — √1 / 2(2)
x1 = (-10) / 4 = 2,5
x2 = (-9) + √1 / 2(2)
x2 = (-8) / 4 = (-2)
բ)16a2 — 40a + 25 = 0
D = b2 — 4ac
D = 402 — 4(16 * 25)
D = 1600 — 1600 = 0
D = 0
x = -(b / 2a)
x = -(40 / 2(16))
x = -(40 / 32) = -1,25
գ)x2 — 8x + 16 = 0
D = b2 — 4ac
D = (-8)2 — 4(1 * 16)
D = 64 — 64 = 0
D = 0
x = -(b / 2a)
x = -(8 / 2(1))
x = -(8 / 1) = -8
դ)9z2 — 30z + 25 = 0
D = b2 — 4ac
D = (-30)2 — 4(9 * 25)
D = 900 — 900 = 0
D = 0
x = -(b / 2a)
x = -(30 / 2(9))
x = -(30 / 18) = 1,666666666666667
ե)7x2 — 13x — 20 = 0
D = b2 — 4ac
D = (-13)2 — 4(7 * (-20))
D = 169 + 560 = 729
D > 0
x = (-b) ± √D / 2a
x1 = (-13) — √729 / 2(7)
x1 = -42 / 14 = -3
x2 = (-13) + √729 / 2(7)
x2 = 16 / 14 = 1,142857142857143
Ղազարյան Արփի 