Question

Решите плиз два неравенства

1) 9х -11>5(2х-3)

2) х^2 + 7х -8 ≥ 0

Answer 1

1) 9х -11>5(2х-3)

9x-11>10x-15

  9x-10x>-15+11

   -1x>-4    *(-1)

   x<4

(-бесконечност;4) 

 2) х^2 + 7х -8 ≥ 0
D = b2 - 4ac
D = 49 + 32 = 81 = 9^2

x1,2 = -b ± √D/2a
x1 = -7 + 9/2 = 2/2 = 1
x2 = -7 - 9/2 = - 16/2 = -8
Ответ: x1 = 1; x2 = -8(не удол)

1^2+7+1-8>=0

8-7>=0

1>=0

[1;бесконечност+)