Answer:
14
Explanation:
Note: i^2 = -1
4 + 2i(sqrt10) - 2i(sqrt10) - i^2(sqrt(100))
= 4 - (-10)
= 4 + 10
= 14
Remember the difference of squares:
a² - b² = (a + b)(a - b)
Therefore (2 + i√10)(2 + i√10)
= 2² - (i√10)²
= 4 - (10i²)
= 4 - (10)(-1) because i² = -1
= 14.
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