5 + 7n=-23 A) (5) B) (-4 C) (-5) D) (11)
1 answer:
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Answer:
x= 0 , ,
Step-by-step explanation:
Given, equation is +
=
. →→→ (1)
Now, by cubing the equation on both sides, we get
( +
)³ = (
)³
⇒ (15x-1) + (13x+1) + 3××
(
+
) = 64 x.
⇒ 28x + 3××
(
) = 64x.
(since from (1), +
=
)
⇒ 12× ×
(
)= 36x.
⇒ 3x = .
Now, once again cubing on both sides, we get
(3x)³ = ()³.
⇒ 27x³ = (15x-1)(13x+1)(x).
⇒ 27x³ = 195x³ + 2x² - x
⇒ 168x³ + 2x² - x = 0
⇒ x(168x² + 2x -1) = 0
⇒ by, solving the equation we get ,
x = 0 ; x = ; x =
therefore, solution is x= 0 , ,