2 + 1 > 10-, 2 + 7x<2, (x + 2)(2x-3) > 0 .
:
. f(x) g(x) - X. f () >g(x) f(x) <g(x) . X .
X, , . - .
, 2 + 7 > 10 -, R, = 5, 2∙5 + 7 > 10 - 5 - . - (1, ∞), , : 2+ 7> 10- => 3>3 => >1.
.
. , .
, 2 + 7> 10 2>3 , (, ∞).
. .
3. f(x) >g(x) X h(x) - , . f () > g(x) f(x) + h(x) = g(x) + h(x) X.
, :
1) f(x) > g(x) d, f(x) + d > g(x) + d, .
2) - ( ) , , , .
4. f () > g(x) X h(x) - , , X h(x) . f () > g(x) f(x) ∙h(x) > g(x) ∙h(x) X.
: f () > g(x) d, f(x)-d> g(x) ∙d, .
5. f () > g(x) X h(x)- , , X h(x) . f () > g(x) f(x) ∙h(x) < g(x) ∙h(x) X.
: f(x) > g(x) d , f(x) ∙d < g(x) ∙d, .
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5x-5<2x-16, x R, , .
1. 2 , -5 , : 5-2<16 + 5 2. : 3 < 21. 3: < 7. 3. 3: < 7. | 2 3, , . - : . 4, , . |
< 7 (-∞, 7) , , 5- 5 < 2 + 16 (-∞, 7).