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Question:
How many identities are there for Algebraic Expressions
Answer:

An algebraic identity is an equality that holds for any values of its variables.

Ex: The identity

(a + b)2 = a2 + b2 + 2ab

holds for all values of a and b.

There are some important algebraic identities are:

1. (a + b)2 = a2 + b2 + 2ab

Ex: (101)2 = (100 + 1)2 = (100)2 + 12 + 2 * 100 * 1 = 10000 + 1 + 200 = 10201

2. (a - b)2 = a2 + b2 - 2ab

Ex: (99)2 = (100 - 1)2 = (100)2 + 12 - 2 * 100 * 1 = 10000 + 1 - 200 = 10001 - 200 = 9801

3. a2 - b2 = (a - b)*(a + b)

Ex: (x2 - 25) = x2 - 52 = (x - 5)*(x + 5)

4. (x + a)*(x + b) = x2 + (a + b)x + ab

Ex: (x + 5)*(x + 2) = x2 + (5 + 2)x + 5*2 = x2 + 7x + 10

5. (x - a)*(x - b) = x2 - (a + b)x + ab

Ex: (x - 5)*(x - 2) = x2 - (5 + 2)x + 5*2 = x2 - 7x + 10

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