Page 172 - aljaber
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QUY@ @pbåîbjn¾a
6 < x < 10 x
.x = 7 .4 < x < 8
:( ) ( )
x < 5 1.6 < x + 1 ⇔ x < 5 ×1.27 < x + 1
⇔ x < 6.32 < x + 1
. 5.32 < x < 6.32 . x > 5.32 x < 6.32
.x = 6
:( ) ()
6912 < 4n3 < 13500 ⇔ 1728 < n3 < 3375
⇔ 3 1728 < 3 n3 < 3 3375
⇔ 12 < n < 15
14 13
. 27
. :( ) ( )
z2 > 0 . ( ) ( )
x >y z <0 .
.( ) .xz < yz
:( ) ( )
. .d = 1 c = −2 b = 1 a = 1
d = 1 c = −2 b = 1 a = 0
.