Page 211 - aljaber

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2 γβα
α+β +γ
) α=2
.(

β + γ = 16 = 3 + 13 = 5 + 11

γ = 13 β = 3 .

αβ + βγ + γα = 2 × 3 + 3 ×13 + 13 × 2 = 71 ()

. γ = 11 β = 5 .
.k = 2 × 5 ×11 = 110

:( )

f (−7) = −77 ×a − 73 ×b − 7c − 5 = 7
⇒ 77 ×a + 73 ×b + 7c = −12

. f (7) = 77 ×a + 73 ×b + 7c − 5 = −12 − 5 = −17 )

:( ) (

x 3 + px2 + qx + 15 = (x − α1 )(x − α2 )(x − α3 )

( )= x2 − (α1 + α2 )x + α1α3 (x − α3 )
( )= x2 + α1α3 (x − α3 )

= x 3 − α3x 2 + α1α2x − α1α2α3

.−α1α2α3 = +15 α1α2 = q p = −α3

. pq = −α1α2α3 = 15

x2 − 9 f (x) :( ) ()