Question

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Answer 1

Answer:

The answer to your question is given below.

Step-by-step explanation:

To which of the above expression is a sum or difference of cube, or not a sum or difference of cube, we shall do the following simplification:

Note: The Cube root of a particular number is simply a multiplication of an identical number in three places.

64x³ – 216

64 has a cube root of 4 and 216 has a cube root of 6. Therefore, the above expression can be written as:

4³x³ – 6³

(4x)³ – 6³

64x³ – 216 = (4x)³ – 6³

Therefore, 64x³ – 216 can be expressed as a difference of cube.

8x^9 + 27

8 has a cube root of 2, x^9 has a cube root of x³ and 27 has a

cube root of 3. Therefore, the above expression can be written as:

2³(x³)³ + 3³

(2x³)³ + 3³

8x^9 + 27 = (2x³)³ + 3³

8x^9 + 27 can be expreessed as a sum of cube

x³ + 125

125 has a cube root of 5. Therefore, the above expression can be written as:

x³ + 5³

x³ + 125 = x³ + 5³

x³ + 125 can be expressed as a sum of cube

36x³ + 121

36 and 121 has no cube root. Therefore, the above expression is not a sum or difference of cube.

x^6 – 16

x^6 has a cube root of x² and 16 has no cube root. Therefore, the above expression is not a sum or difference of cube.

Summary:

Sum or Difference of cubes

64x³ – 216

8x^9 + 27

x³ + 125

Not a Sum or Difference of cubes

36x³ + 121

x^6 – 16