Page 176 - aljaber

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x>5⇒ 5 <5
x +1 6

x >5⇒x >1
5

. 5 < 5 <1<x .5 x
x +1 6 5
x +1 5

.5

x +1

() .8 +c > 4 +c 8 > 4 :( ) ()
()
( ) c=0 ( ) c≤0 ()
()
.c ≥ 0 ()

:( )

1 ≤ 2x − 1 ≤ 11 ⇔ 2 ≤ 2x ≤ 12 ⇔ 1 ≤ x ≤ 6
6−1 = 5

:( )

−2.4 < x < −1.5 ⇒ −2.4p < px < −1.5p

⇒ −2.4p < px < 0

x2 − y2 :( )

.y2 x2

x 2 − y2 = (−6 )2 − 0 = 36

:( )

(x − 1)2 ≥ 0 ⇔ x 2 − 2x + 1 ≥ 0
⇔ x 2 + 1 ≥ 2x
⇔ x +1 ≥2
x