Math Problem Statement

(x + a)^3 = x^3 + px^2 + qx + 64 for all values of x. Solve for p and q.

Solution

The equation given in the image is:

(x+a)3=x3+px2+qx+64(x + a)^3 = x^3 + px^2 + qx + 64

We need to solve for the constants pp and qq.

Step-by-Step Solution

  1. Expand the Left Side:
    Let's expand the left side of the equation using the binomial expansion formula:

    (x+a)3=x3+3ax2+3a2x+a3(x + a)^3 = x^3 + 3ax^2 + 3a^2x + a^3

  2. Equate Coefficients:
    Now, compare this expansion with the right side of the equation:

    x3+3ax2+3a2x+a3=x3+px2+qx+64x^3 + 3ax^2 + 3a^2x + a^3 = x^3 + px^2 + qx + 64

    Equating the coefficients of like terms on both sides:

    • Coefficient of x2x^2: 3a=p3a = p
    • Coefficient of xx: 3a2=q3a^2 = q
    • Constant term: a3=64a^3 = 64
  3. Solve for aa, pp, and qq:

    • From a3=64a^3 = 64, we find:

      a=643=4a = \sqrt[3]{64} = 4

    • Substitute a=4a = 4 into the expressions for pp and qq:

      p=3a=3×4=12p = 3a = 3 \times 4 = 12

      q=3a2=3×42=3×16=48q = 3a^2 = 3 \times 4^2 = 3 \times 16 = 48

Solution:

  • p=12p = 12
  • q=48q = 48

Would you like more details on the binomial expansion or have any questions? Here are some related questions:

  1. How does the binomial theorem work for higher powers?
  2. What are some other ways to expand polynomials?
  3. What if we had a different cubic equation to compare with?
  4. How do we solve for constants in equations involving polynomials?
  5. What if the constants are complex numbers?

Tip: Always equate coefficients of like terms when comparing polynomials to solve for unknowns efficiently.

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Math Problem Analysis

Mathematical Concepts

Algebra
Binomial Expansion
Polynomial Equations

Formulas

(x + a)^3 = x^3 + 3ax^2 + 3a^2x + a^3

Theorems

Binomial Theorem
Equating Coefficients

Suitable Grade Level

Grades 9-12