Math Problem Statement

Find the discriminant of each quadratic equation then state the number of real and imaginary solutions

Find the discriminant of each quadratic equation then state the number of real and imaginary solutions

Solution

Let's analyze each quadratic equation, find its discriminant, and then determine the number of real or imaginary solutions based on that discriminant.

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

Δ=b24ac\Delta = b^2 - 4ac

Based on the value of Δ\Delta:

  • If Δ>0\Delta > 0, the equation has 2 distinct real solutions.
  • If Δ=0\Delta = 0, the equation has 1 real solution (a repeated root).
  • If Δ<0\Delta < 0, the equation has 2 complex (imaginary) solutions.

Now, let's calculate the discriminants for each of the quadratic equations:

1. 2x28x14=6-2x^2 - 8x - 14 = 6

Rewrite the equation as: 2x28x146=0-2x^2 - 8x - 14 - 6 = 0 2x28x20=0-2x^2 - 8x - 20 = 0 Here, a=2a = -2, b=8b = -8, and c=20c = -20.

Discriminant: Δ=(8)24(2)(20)=64160=96\Delta = (-8)^2 - 4(-2)(-20) = 64 - 160 = -96 Since Δ<0\Delta < 0, this equation has 2 complex (imaginary) solutions.

2. 9n23n8=109n^2 - 3n - 8 = -10

Rewrite the equation as: 9n23n8+10=09n^2 - 3n - 8 + 10 = 0 9n23n+2=09n^2 - 3n + 2 = 0 Here, a=9a = 9, b=3b = -3, and c=2c = 2.

Discriminant: Δ=(3)24(9)(2)=972=63\Delta = (-3)^2 - 4(9)(2) = 9 - 72 = -63 Since Δ<0\Delta < 0, this equation has 2 complex (imaginary) solutions.

3. 9m2+6m+659m^2 + 6m + 6 \geq 5

Rewrite the inequality as: 9m2+6m+6509m^2 + 6m + 6 - 5 \geq 0 9m2+6m+109m^2 + 6m + 1 \geq 0 Here, a=9a = 9, b=6b = 6, and c=1c = 1.

Discriminant: Δ=624(9)(1)=3636=0\Delta = 6^2 - 4(9)(1) = 36 - 36 = 0 Since Δ=0\Delta = 0, this quadratic inequality has 1 real solution (a repeated root). However, because it's an inequality, the quadratic is non-negative (always greater or equal to 0) for all values of mm, meaning all real numbers will satisfy the inequality.

4. 9b2=8b+89b^2 = -8b + 8

Rewrite the equation as: 9b2+8b8=09b^2 + 8b - 8 = 0 Here, a=9a = 9, b=8b = 8, and c=8c = -8.

Discriminant: Δ=824(9)(8)=64+288=352\Delta = 8^2 - 4(9)(-8) = 64 + 288 = 352 Since Δ>0\Delta > 0, this equation has 2 distinct real solutions.

Summary of Results:

  1. Equation 1: 2 complex (imaginary) solutions.
  2. Equation 2: 2 complex (imaginary) solutions.
  3. Equation 3: 1 real solution (non-negative for all mm).
  4. Equation 4: 2 distinct real solutions.

Would you like further details or clarifications on any of these steps?


Here are 5 related questions:

  1. How do you solve quadratic equations using the quadratic formula?
  2. What is the significance of the discriminant in determining solution types?
  3. Can a quadratic inequality have complex solutions?
  4. How do you solve systems involving quadratic equations?
  5. What are some real-world applications of quadratic equations?

Tip: When solving a quadratic equation, always simplify the equation first to standard form ax2+bx+c=0ax^2 + bx + c = 0 to apply formulas effectively.

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Math Problem Analysis

Mathematical Concepts

Quadratic Equations
Discriminant

Formulas

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

Theorems

Discriminant Theorem: Δ > 0 (2 real solutions), Δ = 0 (1 real solution), Δ < 0 (2 complex solutions)

Suitable Grade Level

Grades 9-12