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Simplify square roots of perfect squares

The learner interprets a square root as the principal nonnegative number whose square equals the radicand and evaluates square roots of perfect-square nonnegative integers, such as 81=9\sqrt{81}=9 and 0=0\sqrt{0}=0. This includes recognizing perfect-square structure and avoiding the misconception that a2=a\sqrt{a^2}=a for negative aa; general radical simplification, irrational roots, and complex roots are beyond this scope.

Detailed Explanation: Simplify square roots of perfect squares

A square root asks: What nonnegative number, multiplied by itself, gives the number inside the radical?

To simplify n\sqrt{n}:

  1. Recognize whether nn is a perfect square.
  2. Find the nonnegative number whose square is nn.
  3. Write that number as the answer.

Example: Simplify 144\sqrt{144}.

Find a number that squares to 144144:

122=1212=14412^2=12\cdot 12=144

Because a square root means the principal nonnegative square root,

144=12\sqrt{144}=12

Notice that (12)2(-12)^2 is also 144144, but 144\sqrt{144} is 1212, not 12-12, because square roots are defined to be nonnegative. Similarly, 0=0\sqrt{0}=0.

Learn by doing: Simplify square roots of perfect squares

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Square Roots of Perfect Squares


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