Math Problem Statement

What value(s) of b will cause 27x^2 + bx + 3 = 0 to have one real solution?

Solution

To determine the value(s) of bb that will cause the equation 27x2+bx+3=027x^2 + bx + 3 = 0 to have one real solution, we use the discriminant of a quadratic equation.

For a quadratic equation of the form ax2+bx+c=0ax^2 + bx + c = 0, the discriminant Δ\Delta is given by:

Δ=b24ac\Delta = b^2 - 4ac

If the equation has one real solution, the discriminant must be zero:

b24ac=0b^2 - 4ac = 0

In this case:

  • a=27a = 27
  • b=bb = b (unknown, what we are solving for)
  • c=3c = 3

Substituting these values into the discriminant formula:

b24(27)(3)=0b^2 - 4(27)(3) = 0

Simplify:

b2324=0b^2 - 324 = 0

Solving for bb:

b2=324b^2 = 324 b=±324b = \pm \sqrt{324} b=±18b = \pm 18

Thus, the values of bb that will cause the equation to have one real solution are 18 and -18.

The correct answer is therefore:

  • 18, -18

Would you like further details or have any questions?


Here are some follow-up questions for further practice:

  1. What is the discriminant, and how does it determine the nature of the solutions of a quadratic equation?
  2. If b=21b = 21 in the equation 27x2+bx+3=027x^2 + bx + 3 = 0, how many solutions would there be and what type?
  3. How does changing the constant term cc affect the values of bb that result in one real solution?
  4. What would the value of cc need to be if b=18b = 18 for the equation to still have one real solution?
  5. If the quadratic equation had a=1a = 1 instead of a=27a = 27, what values of bb would make the discriminant zero?

Tip: Remember, when the discriminant is positive, the quadratic equation has two real solutions; if it's zero, there is one real solution; and if it's negative, there are no real solutions (only complex).

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Discriminant

Formulas

Discriminant formula: Δ = b^2 - 4ac

Theorems

Discriminant theorem

Suitable Grade Level

Grades 10-12