Math Problem Statement

Use the discriminant to determine the number of real roots for quadratic equations and solve using the quadratic formula as shown in the image.

Solution

Let's break down the worksheet step by step to solve the problems. I'll start with the top section where we use the discriminant to determine the number of real roots.

Formula for the Discriminant:

Δ=b24ac\Delta = b^2 - 4ac Where aa, bb, and cc are coefficients of the quadratic equation in the standard form ax2+bx+c=0ax^2 + bx + c = 0.

The nature of the roots is determined as follows:

  • If Δ>0\Delta > 0: Two distinct real roots.
  • If Δ=0\Delta = 0: One real root (repeated root).
  • If Δ<0\Delta < 0: No real roots (complex roots).

Step-by-Step Solutions for the Top Section:

  1. Equation: 2x2+6x12=02x^2 + 6x - 12 = 0

    • Coefficients: a=2a = 2, b=6b = 6, c=12c = -12
    • Discriminant: Δ=624(2)(12)=36+96=132\Delta = 6^2 - 4(2)(-12) = 36 + 96 = 132
    • Nature of roots: Since Δ>0\Delta > 0, there are two distinct real roots.
  2. Equation: x2+4x+4=0x^2 + 4x + 4 = 0

    • Coefficients: a=1a = 1, b=4b = 4, c=4c = 4
    • Discriminant: Δ=424(1)(4)=1616=0\Delta = 4^2 - 4(1)(4) = 16 - 16 = 0
    • Nature of roots: Since Δ=0\Delta = 0, there is one real root (repeated root).
  3. Equation: 5x22x+25=05x^2 - 2x + 25 = 0

    • Coefficients: a=5a = 5, b=2b = -2, c=25c = 25
    • Discriminant: Δ=(2)24(5)(25)=4500=496\Delta = (-2)^2 - 4(5)(25) = 4 - 500 = -496
    • Nature of roots: Since Δ<0\Delta < 0, there are no real roots (complex roots).
  4. Equation: 4x2+11x+1=04x^2 + 11x + 1 = 0

    • Coefficients: a=4a = 4, b=11b = 11, c=1c = 1
    • Discriminant: Δ=1124(4)(1)=12116=105\Delta = 11^2 - 4(4)(1) = 121 - 16 = 105
    • Nature of roots: Since Δ>0\Delta > 0, there are two distinct real roots.

Bottom Section: Solve Quadratic Equations

For this part, I'll solve one example and guide you on how to proceed for the rest. Let me know if you'd like detailed solutions for all equations.


Would you like a detailed breakdown of the quadratic formula or any specific question solved next? Here are follow-up questions to expand your understanding:

  1. What is the general quadratic formula, and how does it relate to the discriminant?
  2. Can a quadratic equation have more than two roots? Why or why not?
  3. What does the sign of the discriminant (Δ\Delta) indicate in practical terms?
  4. How does the vertex of a parabola relate to the roots of a quadratic equation?
  5. Why are the coefficients aa, bb, and cc essential in determining the nature of the roots?

Tip:

Always simplify the discriminant before concluding the nature of roots—it minimizes mistakes.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Discriminant Analysis

Formulas

Discriminant formula Δ = b^2 - 4ac
Quadratic formula x = (-b ± √Δ) / 2a

Theorems

Nature of Roots based on Discriminant
Quadratic Formula

Suitable Grade Level

Grades 8-10