Page 258 - aljaber

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x − 2 = 6 − x ⇒ 2x = 8 ⇒ x = 4

.d = 2 2, 4, 6

.y2 = 2 × 6 = 12 ⇒ y = 2 3 2, y, 6

.r = 3 2, 2 3, 6

. 3r = 3 × 3 = 3 :( ) ()
()
d 22

.a1r 6 = 8 a1r 2 = 2

a1r 6 = 8
a1r 2 2

( )r 4 = 4 = 4

2

.a1 = 1 ( )r= 2

( )S6 = 12 6 − 1 = 7 = 7(1 + 2) = 7 2 + 7
2 −1
2 −1

c=7 b=2 a=7

.a + b + c = 7 + 2 + 7 = 16

:( )

16 = S8 = 8  2 × (−5) + 7d 
2

4 = −10 + 7d

7d = 14

d =2

d =2 d, d2, d 3, d 4, d 5, d6

.d = 2