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If m + 1/m = 4 then what is m³ + 1/m³

A48

B52

C42

D54

Answer:

B. 52

Read Explanation:

Algebraic Simplification and Identities

Understanding the Problem

The question involves finding the value of an expression involving powers of a variable and its reciprocal, given a relationship between the variable and its reciprocal.

Key Algebraic Identity

  • The core identity used here is the sum of cubes formula: (a + b)³ = a³ + b³ + 3ab(a + b)

Applying the Identity

In this problem, let a = m and b = 1/m.

  • Substituting these into the identity: (m + 1/m)³ = m³ + (1/m)³ + 3(m)(1/m)(m + 1/m)

  • This simplifies to: (m + 1/m)³ = m³ + 1/m³ + 3(m + 1/m)

Using the Given Information

We are given that m + 1/m = 4.

  • Substitute the given value into the simplified identity: (4)³ = m³ + 1/m³ + 3(4)

Calculation

  • Calculate the cube of 4: 4³ = 64

  • Calculate the product of 3 and 4: 3 * 4 = 12

  • The equation becomes: 64 = m³ + 1/m³ + 12

Isolating the Target Expression

To find the value of m³ + 1/m³, rearrange the equation:

  • m³ + 1/m³ = 64 - 12

  • m³ + 1/m³ = 52


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