Page 2 - LN-4-Standard Identities
P. 2
= 250000 + 1500 + 2
= 251502
2
Example: Consider (x + 1) (x + 3) = x + 4x + 3.
Standard Identities:
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2
(i) (a +b) = (a + 2ab + b )
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2
2
2
(ii) (a – b) = (a - 2ab + b )
(iii) (a + b) (a – b) = (a – b )
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2
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Prove that (3a + 7) – 84a = (3a – 7) .
Solution: LHS = (3a + 7) – 84a
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2
2
= (3a) + 2(3a)(7) + (7) – 84a
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= 9a + 42a + 49 – 84a
= 9a – 42a + 49
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RHS = (3a – 7) 2
= (3a) – 2(3a)(7) + (7) 2
2
MUST KNOW:
