Page 247 - aljaber

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. 5, 7, 9, 11,…, 87 :( ) (.)

d =2 a1 = 5 .an = 87 ()
r
an = a1 + (n − 1)d ()
87 = 5 + 2(n − 1) ()
2n = 84
.n = 42 ()

a , a, ar :( )
r .

a3 = a ×a ×ar = 27
r

.a = 3 27 = 3

:( )

3−1 = 1−3 = 2
55 55
4 − 2 =/ 8 − 4

3 − 1 =/ 27 − 3 ()
5 3 25 5
1 − 1 =/ 1 − 1 )
32 43

.2

5

. f (x) = (x − 11)(x − 7)(x − 3):(

.11 7 3