Page 200 - aljaber
P. 200
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y =7
x 2 + 3x + 9 = 0 y = −9
x2 + x +1
. 9 − 36 = −27 < 0
. x 2 + 3x − 7 = 0
x = −3 ± 9 + 28 = −3 ± 37
22
.x2 = −3 − 37 x1 = −3 + 37
2 2
x9 + x4 −x −1 ()
.x5 + x + 1
( ) ( )x 9 + x 4 − x − 1 = x9 − x + x 4 − 1
= x (x8 −1) + (x4 −1)
= x (x4 −1)(x4 + 1) + (x4 − 1)
= (x4 − 1)(x5 + x + 1)
.x5 + x +1 x2 + x +1
.x3 − x2 + 1 x2 + x +1 x5 + x +1
.(x − 1)(x + 1)(x2 + 1)(x2 + x + 1)(x 3 − x 2 + 1)
