Quadratic Equations - Examples & Applications

This section provides step-by-step examples on how to solve quadratic equations of the form ax2+bx+c=0ax^2 + bx + c = 0. You will learn to determine the best method for solving, whether it's factoring, completing the square, or applying the quadratic formula.

Vieta's Formulas

Vieta's formulas provide a direct relationship between the roots of a polynomial and its coefficients. For ax2+bx+c=0ax^2 + bx + c = 0 with roots r1r_1 and r2r_2, the sum of the roots is b/a-b/a and the product is c/ac/a.

Example

Example 1: Finding Sum and Product (Basic) Without solving the equation, find the sum and product of the roots for 2x25x3=02x^2 - 5x - 3 = 0.

Step-by-Step Solution

0 of 3 Steps Completed
1

The Discriminant (Δ\Delta)

The discriminant (Δ=b24ac\Delta = b^2 - 4ac) determines the nature of the roots of a quadratic equation. It tells you whether there are two real roots, one real root, or two complex roots.

Example

Case Study 1: Determining the Number of Solutions Use the discriminant to determine the number and type of solutions for the equation: 2x25x+3=02x^2 - 5x + 3 = 0.

Step-by-Step Solution

0 of 3 Steps Completed
1

Example

Case Study 2: Identifying Complex Roots Use the discriminant to classify the roots of the equation: x2+4x+7=0x^2 + 4x + 7 = 0.

Step-by-Step Solution

0 of 3 Steps Completed
1

The Standard Form

A quadratic equation must be in the form ax2+bx+c=0ax^2 + bx + c = 0 before you can solve it using most methods.

Example

Example 1: Solving by Factoring (Basic) Solve the equation by factoring: x28x+15=0x^2 - 8x + 15 = 0.

Step-by-Step Solution

0 of 3 Steps Completed
1

Example

Example 2: Factoring with a Leading Coefficient a>1a > 1 (Intermediate) Solve the equation by factoring: 3x2+10x8=03x^2 + 10x - 8 = 0.

Step-by-Step Solution

0 of 4 Steps Completed
1

Example

Example 3: Solving using the Quadratic Formula (Intermediate) Solve the equation using the quadratic formula: 2x27x4=02x^2 - 7x - 4 = 0.

Step-by-Step Solution

0 of 4 Steps Completed
1

Example

Example 4: Completing the Square (Advanced) Solve the equation by completing the square: x2+6x7=0x^2 + 6x - 7 = 0.

Step-by-Step Solution

0 of 4 Steps Completed
1