(×+1)³-×(×+1)²+(×+1)
Answers
Answer:
OR
Step-by-step-explanation:
NOTE :Kindly refer to the attachment first.
We have given that
By using some identities, we can find the value of the given expression.
( x + 1 )³ - x ( x + 1 )² + ( x + 1 ) = 0
⟹ x³ + 3x² + 3x + 1 - x ( x² + 2x + 1 ) + ( x + 1 )=0
⟹ x³ + 3x² + 3x + 1 - x³ - 2x² - x + x + 1 = 0
⟹ 3x² + 3x + 1 - 2x² + 1 = 0
⟹ 3x² - 2x² + 3x + 1 + 1 = 0
⟹ x² + 3x + 2 = 0
⟹ x² + 2x + x + 2 = 0
⟹ x ( x + 2 ) + 1 ( x + 2 ) = 0
⟹ ( x + 2 ) ( x + 1 ) = 0
⟹ x + 2 = 0 OR x + 1 = 0
⟹ x = - 2 OR x = - 1
OR
Given :
- ( x + 1 )³ - x ( x + 1 )² + ( x + 1 )
To Find :
- Value of x
Solution :
➨ ( x + 1 )³ - x ( x + 1 )² + ( x + 1 )
➨ ( x³ + 3x² + 3x + 1 ) - x ( x² + 2x + 1 ) + ( x + 1 )
➨ x³ + 3x² + 3x + 1 - x³ - 2x² -x + x + 1
➨ x³ - x³ + 3x² - 2x² + 3x - x + x + 1 + 1
➨ x² + 3x + 2
By splitting middle term :
➨ x² + 2x + x + 2
➨ x ( x + 2 ) + 1 ( x + 2 )
➨ ( x + 1 ) ( x + 2 )
To Find value of x let this equation = 0
➨ ( x + 1 ) ( x + 2 ) = 0
➨ x + 1 = 0
➨ x = - 1
➨ x + 2 = 0
➨ x = -2
Identities used :
➨ ( a + b )³ = a³ + 3a²b + 3ab² + b³
➨ ( a + b )² = a² + 2ab + b²