If the quadratic equation x^2 + 2x + k = 0 has roots that are both negative, wha

Practice Questions

Q1
If the quadratic equation x^2 + 2x + k = 0 has roots that are both negative, what is the condition on k? (2023)
  1. k > 0
  2. k < 0
  3. k >= 0
  4. k <= 0

Questions & Step-by-Step Solutions

If the quadratic equation x^2 + 2x + k = 0 has roots that are both negative, what is the condition on k? (2023)
  • Step 1: Understand that a quadratic equation is in the form ax^2 + bx + c = 0. Here, a = 1, b = 2, and c = k.
  • Step 2: Recall that the roots of a quadratic equation can be found using the formula: roots = (-b ± √(b² - 4ac)) / (2a).
  • Step 3: For our equation, substitute a, b, and c into the formula: roots = (-2 ± √(2² - 4*1*k)) / (2*1).
  • Step 4: Simplify the expression: roots = (-2 ± √(4 - 4k)) / 2.
  • Step 5: For the roots to be real numbers, the expression inside the square root (the discriminant) must be greater than or equal to 0: 4 - 4k ≥ 0.
  • Step 6: Solve the inequality: 4 ≥ 4k, which simplifies to k ≤ 1.
  • Step 7: Now, for both roots to be negative, the sum of the roots (which is -b/a = -2/1 = -2) must be negative, and the product of the roots (which is c/a = k/1 = k) must be positive.
  • Step 8: Since the product of the roots (k) must be positive, we conclude that k > 0.
  • Step 9: Combine the conditions: k must be greater than 0 and less than or equal to 1, so the final condition is k > 0.
  • Quadratic Equations – Understanding the properties of quadratic equations, particularly the conditions for the nature of roots based on coefficients.
  • Roots of Quadratic Equations – Applying Vieta's formulas to determine the sum and product of roots and their implications on the signs of the roots.
  • Discriminant Analysis – Using the discriminant to ensure that the roots are real and analyzing the conditions for both roots to be negative.
Soulshift Feedback ×

On a scale of 0–10, how likely are you to recommend The Soulshift Academy?

Not likely Very likely