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Evaluate: (A + 1)(A2 - a + 1) and (A - 1)(A2 + a + 1) - Mathematics

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Question

Evaluate: (a + 1)(a2 - a + 1) and (a - 1)(a2 + a + 1) 

Sum

Solution

(a + 1)(a2 - a + 1) and (a - 1)(a2 + a + 1) 

= a (a2 - a + 1) + 1 (a2 - a + 1)

= a3 - a2 + a + a2 - a + 1 

= a3 + 1

(a - 1)(a2 + a + 1)

= a(a2 + a + 1) - 1(a2 + a + 1) 

= a3 + a2 + a - a2 - a - 1 

= a3 - 1

Now, (a + 1)(a2 - a + 1) + (a - 1)(a2 + a + 1)

= a3 + 1 + a3 - 1

= 2a3 

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Performs Operations (Addition and Subtraction) on Algebraic Expressions with Integral Coefficients Only.
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Chapter 11: Fundamental Concepts (Including Fundamental Operations) - Exercise 11 (C)

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Selina Concise Mathematics [English] Class 7 ICSE
Chapter 11 Fundamental Concepts (Including Fundamental Operations)
Exercise 11 (C) | Q 5.4
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