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Question
The real value of ‘a’ for which 3i3 – 2ai2 + (1 – a)i + 5 is real is ______.
Solution
The real value of ‘a’ for which 3i3 – 2ai2 + (1 – a)i + 5 is real is – 2.
Explanation:
3i3 – 2ai2 + (1 – a)i + 5 = –3i + 2a + 5 + (1 – a)i
= 2a + 5 + (–a – 2)i
which is real if –a – 2 = 0
i.e. a = –2.
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