Glencoe Math: Course 3, Volume 1
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Glencoe Math: Course 3, Volume 1 View details
8. Roots
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Exercise 28 Page 77

Think of a number that when multiplied by itself three times results in - 216.

- 6

Practice makes perfect

The cube root of a number a is another number b if b multiplied by itself three times is a. This means that if b is the cube root of a, then b raised to the third power results in a. Let's see some examples of this. sqrt(a)= b because b^3= a [0.8em] c|c sqrt(- 8)= - 2 & sqrt(27)= 3 because( - 2)^3= - 8 & because 3^3= 27 We will now find the cube root of - 216. We need to think of a number that when multiplied by itself three times results in - 216. ?^3= - 216 Since - 6 raised to the third power is - 216, the number we are looking for is - 6.

(- 6)(- 6)(- 6)
(- 6)^3
- 216

This means that the cube root of - 216 is - 6. sqrt(- 216) = - 6