Math Problem Statement

Given that x2 + 8kx + k = 0 has equal roots, find the value of k.

Solution

The quadratic equation is given as:

x2+8kx+k=0x^2 + 8kx + k = 0

For the quadratic equation ax2+bx+c=0ax^2 + bx + c = 0 to have equal roots, the discriminant must be zero. The discriminant Δ\Delta is given by:

Δ=b24ac\Delta = b^2 - 4ac

In this case:

  • a=1a = 1
  • b=8kb = 8k
  • c=kc = k

Thus, the discriminant becomes:

Δ=(8k)24(1)(k)\Delta = (8k)^2 - 4(1)(k) Δ=64k24k\Delta = 64k^2 - 4k

Since the equation has equal roots, we set the discriminant equal to zero:

64k24k=064k^2 - 4k = 0

Factor the equation:

4k(16k1)=04k(16k - 1) = 0

This gives two possible solutions:

  1. 4k=04k = 0, which implies k=0k = 0
  2. 16k1=016k - 1 = 0, which implies k=116k = \frac{1}{16}

Thus, the values of kk are k=0k = 0 or k=116k = \frac{1}{16}.

Would you like more details on how the discriminant works, or do you have any other questions?

Here are 5 related questions:

  1. What are the properties of a quadratic equation with equal roots?
  2. How do you solve quadratic equations by factoring?
  3. What does the discriminant tell us about the nature of the roots of a quadratic equation?
  4. How do you find the roots of a quadratic equation using the quadratic formula?
  5. How do you derive the condition for equal roots in a quadratic equation?

Tip: In quadratic equations, if the discriminant is positive, the roots are real and distinct; if it's zero, the roots are real and equal; and if it's negative, the roots are complex.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Discriminant

Formulas

Quadratic equation: ax^2 + bx + c = 0
Discriminant: Δ = b^2 - 4ac

Theorems

Condition for equal roots in quadratic equations

Suitable Grade Level

Grades 9-11