Solve x² = 100 — x = 10 or x = -10

Problem

$x^2 = 100$

Step-by-step solution

Take the positive and negative square root of both sides.
$x = \pm\sqrt{100} = \pm 10$ .
Always include both signs — squaring loses the sign information.

Answer

$x = 10 \quad \text{or} \quad x = -10$

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