Algebra Tutorials!
Sunday 14th of April  
Exponential Decay
Negative Exponents
Multiplying and Dividing Fractions 4
Evaluating Expressions Involving Fractions
The Cartesian Coordinate System
Adding and Subtracting Fractions with Like Denominators
Solving Absolute Value Inequalities
Multiplying Special Polynomials
FOIL Method
Solving Systems of Equations by Graphing
Graphing Compound Inequalities
Solving Quadratic Equations by Completing the Square
Addition Property of Equality
Square Roots
Adding and Subtracting Fractions
The Distance Formula
Graphing Logarithmic Functions
Dividing Mixed Numbers
Evaluating Polynomials
Power of a Product Property of Exponents
Terminology of Algebraic Expressions
Adding and Subtracting Rational Expressions with Identical Denominators
Solving Exponential Equations
Factoring The Difference of 2 Squares
Changing Fractions to Decimals
Solving Linear Equations
Using Patterns to Multiply Two Binomials
Completing the Square
Roots of Complex Numbers
Methods for Solving Quadratic Equations
Conics in Standard Form
Solving Quadratic Equations by Using the Quadratic Formula
Simplifying Fractions 2
Exponential Notation
Exponential Growth
The Cartesian Plane
Graphing Linear Functions
The Slope of a Line
Finding Cube Roots of Large Numbers
Rotating Axes
Common Mistakes With Percents
Solving an Equation That Contains a Square Root
Rational Equations
Properties of Common Logs
Composition of Functions
Using Percent Equations
Solving Inequalities
Properties of Exponents
Graphing Quadratic Functions
Factoring a Polynomial by Finding the GCF
The Rectangular Coordinate System
Adding and Subtracting Fractions
Multiplying and Dividing Rational Expressions
Improper Fractions and Mixed Numbers
Properties of Exponents
Complex Solutions of Quadratic Equations
Solving Nonlinear Equations by Factoring
Solving Quadratic Equations by Factoring
Least Common Multiples
Solving Exponential Equations
Solving Linear Equations
Multiplication Property of Equality
Multiplying Mixed Numbers
Multiplying Fractions
Reducing a Rational Expression to Lowest Terms
Literal Numbers
Factoring Trinomials
Logarithmic Functions
Adding Fractions with Unlike Denominators
Simplifying Square Roots
Adding Fractions
Equations Quadratic in Form
Dividing Rational Expressions
Slopes of Parallel Lines
Simplifying Cube Roots That Contain Variables
Functions and Graphs
Complex Numbers
Multiplying and Dividing Fractions 1
Composition of Functions
Intercepts of a Line
Multiplying Two Numbers with the same Tens Digit and whose Ones Digits add up to 10
Factoring Trinomials
Exponents and Polynomials
Decimals and their Equivalent Fractions
Negative Integer Exponents
Adding and Subtracting Mixed Numbers
Solving Quadratic Equations
Theorem of Pythagoras
Equations 1
Subtracting Fractions
Solving Quadratic Equations by Graphing
Evaluating Polynomials
Angles and Degree Measure
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Solving Quadratic Equations by Using the Quadratic Formula

Objective Introduce the Quadratic Formula and learn how to use it to solve quadratic equations.

In this lesson, you will use the Quadratic Formula to solve quadratic equations. The goal is that you become comfortable using this formula. This will require lots of practice, and so you should pay special attention to the examples.

The Quadratic Formula The solutions of a quadratic equation in the form ax 2 + bx + c = 0, where a 0, are given by the formula .

This formula can be used to find the solutions to any quadratic equation.

Notice the sign in the formula. This means that there may be two solutions to a quadratic equation. Recall that a parabola intersects the x -axis in two places, the corresponding equation has two solutions. This corresponds to the two solutions .

The expression inside of the square root, b 2 - 4ac, is called the discriminant. When the discriminant is positive, there are two distinct solutions. When this expression is zero, the square root in the Quadratic Formula is zero, and then there is only one solution, . This corresponds to the parabola intersecting the x -axis in only one point, namely the vertex. The final case is when the discriminant b 2 - 4ac is negative, in which case the square root is not defined. In this case, there are no real solutions to the quadratic equation. This corresponds to the parabola not intersecting the x-axis at all.

Solutions of the Quadratic Equation ax 2 + bx + c = 0
Discriminant b 2 - 4ac > 0 b 2 - 4ac = 0 b 2 - 4ac < 0
Number of Solutions





Parabola Intersects the x-axis yes, in two distinct points yes, in exactly one point, the vertex no



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