


Then substitute 1, 2, and –2 for a, b, and c, respectively, in the quadratic formula and simplify. In Example, the quadratic formula is used to solve an equation whose roots are not rational. Then substitute 1 (which is understood to be in front of the x 2), –5, and 6 for a, b, and c, respectively, in the quadratic formula and simplify.īecause the discriminant b 2 – 4 ac is positive, you get two different real roots.Įxample produces rational roots.


One real root if the discriminant b 2 – 4 ac is equal to 0.Two different real roots if the discriminant b 2 – 4 ac is a positive number.A quadratic equation with real numbers as coefficients can have the following: The discriminant is the value under the radical sign, b 2 – 4 ac. These three possibilities are distinguished by a part of the formula called the discriminant. When using the quadratic formula, you should be aware of three possibilities. Where a is the numeral that goes in front of x 2, b is the numeral that goes in front of x, and c is the numeral with no variable next to it (a.k.a., “the constant”). A second method of solving quadratic equations involves the use of the following formula:Ī, b, and c are taken from the quadratic equation written in its general form of This is generally true when the roots, or answers, are not rational numbers. Many quadratic equations cannot be solved by factoring. To check, 2 x 2 + 2 x – 1 = x 2 + 6 x – 5 X 2 – 6 x = 16 becomes x 2 – 6 x – 16 = 0īoth values, 8 and –2, are solutions to the original equation.Ī quadratic with a term missing is called an incomplete quadratic (as long as the ax 2 term isn't missing).įirst, simplify by putting all terms on one side and combining like terms. Check by inserting your answer in the original equation.Put all terms on one side of the equal sign, leaving zero on the other side.To solve a quadratic equation by factoring, There are three basic methods for solving quadratic equations: factoring, using the quadratic formula, and completing the square. Quiz: Linear Inequalities and Half-PlanesĪ quadratic equation is an equation that could be written as.Solving Equations Containing Absolute Value.Inequalities Graphing and Absolute Value.Quiz: Operations with Algebraic Fractions.Quiz: Solving Systems of Equations (Simultaneous Equations).Solving Systems of Equations (Simultaneous Equations).Quiz: Variables and Algebraic Expressions.Quiz: Simplifying Fractions and Complex Fractions.Simplifying Fractions and Complex Fractions.Quiz: Signed Numbers (Positive Numbers and Negative Numbers).Signed Numbers (Positive Numbers and Negative Numbers).Quiz: Multiplying and Dividing Using Zero.Quiz: Properties of Basic Mathematical Operations.Properties of Basic Mathematical Operations.
