If (a + bi)(a - bi) = 29 and a + b = 7 then a²+b² equals?
- 29
- 30
- 31
- None of these
Explanation
(a + bi)(a - bi) = a² - (bi)² = a² - b²i²
Since i² = -1, this becomes a² - b²(-1) = a² + b²
Given (a + bi)(a - bi) = 29, so a² + b² = 29
Last verified on 09-05-2026
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