Ex 10.3, 7 - Chapter 10 Class 12 Vector Algebra

Last updated at August 8, 2026 by

Ex 10.3, 7 - Evaluate product (3a - 5b).(2a + 7b) - Class 12

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Ex 10.3, 7 Evaluate the product (3š‘Ž āƒ— āˆ’ 5š‘ āƒ—) ā‹… (2š‘Ž āƒ— + 7š‘ āƒ—). (3š‘Ž āƒ— āˆ’ 5š‘ āƒ—) ā‹… (2š‘Ž āƒ— + 7š‘ āƒ—) = 3š‘Ž āƒ— . 2š‘Ž āƒ— + 3š‘Ž āƒ—.7š‘ āƒ— āˆ’ 5š‘ āƒ—.2š‘Ž āƒ— āˆ’ 5š‘ āƒ—. 7š‘ āƒ— = 6(š‘Ž āƒ—. š‘Ž āƒ—) + 21(š‘Ž āƒ—. š‘ āƒ—) āˆ’ 10 (š’ƒ āƒ—. š’‚ āƒ—) āˆ’ 35 (š‘ āƒ—. š‘ āƒ—) = 6(š‘Ž āƒ—. š‘Ž āƒ—) + 21(š‘Ž āƒ—. š‘ āƒ—) āˆ’ 10 (š’‚ āƒ—. š’ƒ āƒ—) āˆ’ 35 (š‘ āƒ—. š‘ āƒ—) = 6(š’‚ āƒ—. š’‚ āƒ—) + 11 (š‘Ž āƒ—. š‘ āƒ—) āˆ’35 (š’ƒ āƒ—. š’ƒ āƒ—) = 6 |š’‚ āƒ— |2 + 11(š‘Ž āƒ—. š‘ āƒ—) āˆ’ 35 |š’ƒ āƒ— |2 Therefore, (3š‘Ž āƒ— āˆ’ 5š‘ āƒ—) ā‹… (2š‘Ž āƒ— + 7š‘ āƒ—) = 6|š’‚ āƒ— |2 + 11 (š’‚ āƒ—. š’ƒ āƒ—) āˆ’ 35 |š’ƒ āƒ— |2

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