Page 155 - aljaber
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7 − 2x +++ +++ −−−
−−− +++ +++
x −3
7 − 2x −+−
x −3
x ≥7 x <3
3
. 2x − 3 < 7 < x + 5 .
()
2x − 3 < 7 ⇔ 2x < 10 ⇔ x < 5
7<x +5 ⇔2<x
.2 < x < 5
AC = 6 AB = 5 ABC ( )
. BC
: .BC = x
BC < AB + AC ⇔ x < 5 + 6 ⇔ x < 11
AC < AB + BC ⇔ 6 < 5 + x ⇔ 1 < x
AB < AC + BC ⇔ 5 < 6 + x ⇔ −1 < x
.1 < x < 11 x >0
. ()
300 . 40
.
