← CBSE Class 10 (age 15) Mathematics ยท Quadratic Equations

Nature of Roots and Discriminant

Practice Quiz

Q1. What is the formula for the discriminant?

โœ” The discriminant D is calculated as b squared minus four ac.

Q2. If D equals zero, what are the roots?

โœ” When discriminant is zero, the quadratic equation has two real and equal roots.

Q3. Find D for x^2 + 5x + 6 = 0.

โœ” D equals 25 minus 24, which results in positive one.
Show transcript
[Slide 1] What Determines the Roots?
Welcome students. Today we learn how to predict roots without solving fully. The key lies in a special value called the discriminant.

[Slide 2] Meet the Discriminant
Calculate D using coefficients a, b, and c. This value decides if roots are real or not. Memorize this formula for your boards.

[Slide 3] Solving a Real Problem
Let's find the nature of roots for this equation. We identify coefficients first to plug into our formula.

[Slide 4] Calculating D Value
Square negative four to get sixteen. Subtract sixteen from sixteen, resulting in zero. This means roots are real and equal.

[Slide 5] Watch Out for Errors
Students often forget squaring the negative sign makes it positive. Also ensure you multiply all three terms correctly.

[Slide 6] Quick Summary Notes
Remember the three cases for board exams. Practice finding D quickly to save time. You are now ready to solve these questions.