### 1. Root of a number

The root of a number *x* is another number, which when multiplied by itself a given number of times, equals x.
For example the second root of 9 is 3, because 3x3 = 9.

- The second root is usually called the square root.
- The third root is susually called the cube root

See

Root (of a number).

### 2. Roots of a polynomial

The roots of a polynomial are the values of the variable that cause the polynomial to evaluate to zero.
For example the roots of
are +2 and -2.

See Roots of a polynomial.

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