Show the following quadratic equation by factorization method: x2… - Vidyadip

Question

Show the following quadratic equation by factorization method:
x² + 10ix - 21 = 0

✓

Answer

x² + 10ix - 21 = 0
⇒ x² + 10ix + 21i² = 0
⇒ x² + 7ix + 3ix + 21i² = 0
⇒ (x + 3i) (x + 7i) = 0
$\therefore\text{x}=-3\text{i},-7\text{i}$

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