1)14 х2-5х-1=0: 2)2 х2+х+67=0: 3)2p2+7p-30=0: 4) - вопрос №32050801142510222670322730042350552112069 от tuzor 17.11.2021 01:50

Question

Алгебра: 1)14 х2-5х-1=0: 2)2 х2+х+67=0: 3)2p2+7p-30=0: 4) y2-3y-5=0: 5) 5x2-11x+2=0: 6)9y2-30y+25=0 решите уравнение ч- в квадрате

tuzor · Answer

1)   14х2 - 5х - 1 = 0
  D = 25 + 56 = 81 Кор.D = 9
x1 = 5 + 9/ 28 = 0,5
  x2 = 5 - 9/ 28 = - 1/7
2) 2x2 + x + 67 = 0
D = 1 - 536 = - 535
Розв'язку немає
3) 2p2 + 7p - 30 = 0
D = 49 + 240 = 289 Kor.D = 17
p1 = -7 + 17/ 4 = 2,5
p2 = -7 - 17/ 4 = - 6
4) y2 - 3y - 5 = 0
D = 9 + 20 = 29 Kor.D = kor z 29
x = 3 + - kor z 29 / 2
5) 5x2 - 11x + 2 = 0
D= 121 - 40 = 81
kor D = 9
x1 = 11 + 9 / 10 = 2
x2 = 11 - 9 / 10 = 0,2
6) 9x2 - 30y + 25 = 0
D = 900 - 900 = 0
x = 30 / 18 = 5/3