Решите неравенства

1) (х - 5) (х-1,5) < 0

2) 0,4 х (7-х) (х-0,8) " 0

" - больше либо равно

1) (x-5) (x-1.5) ∠0

x²-1.5x-5x+7.5∠0

x²-6.5x+7.5∠0

a=1 b=-6.5 c=7.5

x1/2 = (-b+-√ (b²-4ac)) / 2a

x1/2 = (6.5+-√ (42.25-30)) / 2 = (6.5+-√12.25) / 2 = (6.5+-3.5) / 2

x1 = (6.5-3.5) / 2=3/2

x1=1.5

x2 = (6.5+3.5) / 2=10/2

x2=5

2) 0.4 (7-x) (x-0.8) ≤0

0.4 (7x-5.6-x²+0.8x) ≤0

0.4 (-x²+7.8x-5.6) ≤0

-0.4x²+3.12x-2.24≤0

-0.4x²+3.12x-2.24≤0

a=-0.4 b=3.12 c=-2.24

x1/2 = (-b+-√ (b²-4ac)) / 2a

x1/2 = (-3.12+-√ (9.7344-3.584)) / (-0.8) = (-3.12+-√6.1504) / (-0.8)

x1/2 = (-3.12+-2.48) / (-0.8)

x1 = (-3.12-2.48) / (-0.8) = - 5.6 / (-0.8)

x1=7

x2 = (-3.12+2.48) / (-0.8) = - 0.64 / (-0.8)

x2=0.8

x1≤7 x2≤0.8