Evaluate the scalar product (3a − 5b) . (2a + 7b).
Evaluate the scalar product (3a − 5b) . (2a + 7b).
- A. 6|a|² + 11a.b − 35|b|²
- B. 6|a|² − 35|b|²
- C. 6|a|² + 31a.b − 35|b|²
- D. 6|a|² − 11a.b − 35|b|²
Answer: A) 6|a|² + 11a.b − 35|b|²
Explanation: Using distributive property: 6(a.a) + 21(a.b) − 10(b.a) − 35(b.b). Since a.b = b.a, this becomes 6|a|² + 11a.b − 35|b|².
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