Name: solving quadratics by factoring and formula
Uploaded: 2025-11-26T05:44:30.000Z
Duration: 1 min 29 s
Channel: JoVE

The quadratic equation helps solve problems involving area when a variable appears as a squared term.Consider a rectangular garden with a perimeter of 26 meters and an area of 40 square meters. The goal is to find its dimensions.Let one side be the variable, in meters, and express the other side in terms of that variable using the perimeter relationship.Substituting these expressions into the area formula results in a product involving a single variable.Expanding and rearranging this expression leads to a quadratic equation.One method to solve this quadratic equation is by factoring, where the equation is written as a product of two binomials, each set to zero to find the variable&#8217;s values.Another method for solving the equation is completing the square. This involves rewriting the equation by adding a constant to both sides to form a perfect square and taking the square root of both sides.The quadratic formula is a third method for solving quadratic equations. It involves substituting the coefficients of the equation into a standard formula to find the values of the variable.All three methods yield the same solutions, which satisfy the original problem&#8217;s conditions.

quadratic equations

A quadratic equation is an algebraic expression where a variable is raised to the second power and combined with its first power and a constant; all equated to zero. These equations are frequently used to model relationships involving area, motion, and optimization. The general representation of a quadratic equation is<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:50%;'><img style='aspect-ratio:523/74;' src='https://cloudfront.jove.com/files/ftp_upload/40031/40031_Equation_1_editor_40031.svg' alt='40031_Equation_1.svg' /></figure>where a, b, and c are real values, and a is nonzero to ensure the presence of the squared term.One method for solving a quadratic equation involves rewriting it as a product of two linear expressions. This factored form is written as<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:50%;'><img style='aspect-ratio:514/74;' src='https://cloudfront.jove.com/files/ftp_upload/40031/40031_Equation_2_editor_40031.svg' alt='40031_Equation_2.svg' /></figure>In this expression, r and s represent the values that make each factor equal to zero. According to the zero-product property, if the product of two expressions equals zero, then at least one must be zero. As a result, the values represented by r and s are the specific values of the variable that satisfy the equation. Substituting either of these values into the equation produces a true statement, confirming them as solutions.When factoring is not applicable, a more general solution approach is used by applying the standard formula:<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:50%;'><img style='aspect-ratio:649/187;' src='https://cloudfront.jove.com/files/ftp_upload/40031/40031_Equation_3_editor_40031.svg' alt='40031_Equation_3.svg' /></figure>This formula yields all possible equation solutions by substituting the values from the original expression. The term inside the square root, called the discriminant, determines the nature of the solutions. A positive discriminant results in two distinct solutions, a zero discriminant gives one repeated solution, and a negative discriminant indicates that the equation has no real solutions. These methods provide a complete and systematic approach to solving any quadratic equation.

Quadratic Equations

A quadratic equation is an algebraic expression where a variable is raised to the second power and combined with its first power and a constant; all ...

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Math Fundamentals

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Foundations of Mathematics

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solving quadratics by factoring and formula

Quadratic equations are algebraic equations with a variable squared, a first-power term, and a constant term. They are set equal to zero. In high school math, they often help model area, motion, and optimization problems.

The general form of a quadratic equation uses real numbers a, b, and c, with a not equal to zero. The nonzero a value keeps the squared term in the equation. One common way to solve a quadratic is to rewrite it as a product of two linear expressions.

In factored form, the equation is written so that the factors contain values r and s. These values make each factor equal to zero. By the zero-product property, if a product equals zero, then at least one factor must be zero. That means r and s are the values of the variable that satisfy the equation, and substituting either value back into the original equation gives a true statement.

When factoring does not work, the quadratic formula gives a more general method. This formula finds all possible solutions by using the values from the original equation. The expression under the square root is called the discriminant. A positive discriminant gives two different real solutions, a zero discriminant gives one repeated solution, and a negative discriminant means there are no real solutions.

Solving Quadratics by Factoring and Formula

solving-quadratics-by-factoring-and-formula

real number system

Number Types on the Real Line

The real number system brings together the number types used for counting, measuring, and comparing quantities. It includes natural numbers, integers, rational numbers, and irrational numbers. Each set adds new kinds of numbers to the same system. Natural numbers are the basic counting numbers: 1, 2, 3, and so on. Integers extend that set by adding zero and negative whole numbers, such as ..., -3, -2, -1, 0, 1, 2, .... Rational numbers are numbers that can be written as a ratio of two...

real number operations

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exponents

Exponent Rules and Scientific Notation

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radicals

Simplifying Radicals

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algebraic expressions

Simplifying Algebraic Expressions

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rational expressions

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Rational expressions are algebraic fractions with polynomials in the numerator and denominator. They follow the same basic rules as numerical fractions, but variables make them more delicate to work with. A key step is finding values that make the expression undefined, usually because of division by zero or an undefined radical. To determine the domain, start by identifying the values excluded from the denominator. The domain includes all real numbers except those that make the denominator...

linear equations

Solving Linear Equations

Linear equations are a basic algebra tool for modeling constant rates and everyday relationships. They use constants and a single variable, and each term is either a constant or a product of a constant and that variable. When graphed on a Cartesian coordinate plane, they form a straight line that shows a constant rate of change between two quantities. A linear equation in one variable often has the form ax + b = c, where a, b, and c are constants and x is the variable. Solving the equation...

Quadratic equations are algebraic equations with a variable squared, a first-power term, and a constant term. They are set equal to zero. In high school math, they often help model area, motion, and optimization problems. The general form of a quadratic equation uses real numbers a, b, and c, with a not equal to zero. The nonzero a value keeps the squared term in the equation. One common way to solve a quadratic is to rewrite it as a product of two linear expressions. In factored form, the...

complex numbers

Complex Numbers in Solving Equations

Complex numbers extend the real number system so equations with negative square roots can still be solved. The real numbers cannot represent the square root of a negative number. That limits some quadratic equations, especially those with negative discriminants. To solve this problem, mathematicians introduced the imaginary unit i, where i = √(-1). A complex number is written as x + yi, where x and y are real numbers. In this form, x is the real part and y is the imaginary part. The key rule...

quadratic equations in the complex number system

quadratic-equations-in-the-complex-number-system

Complex Roots of Quadratic Equations

Quadratic equations can have real or complex roots, depending on the discriminant. For an equation in the form ax² + bx + c = 0, the coefficients a, b, and c are the numbers that multiply x², x, and the constant term. The discriminant, b² − 4ac, tells us what kind of solutions to expect. When the discriminant is negative, the equation has no real number solutions. In that case, complex numbers provide a way to continue solving the problem. The imaginary unit i is defined by i = √−1, so a...

radical equations

Solving Radical Equations with Checks

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inequalities

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absolute value inequalities

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mathematical modeling: problem solving

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key terms and concepts

Learn how to solve quadratic equations by factoring or with the quadratic formula, and see how the discriminant shows whether there are real solutions.

Solving Quadratics by Factoring and Formula | JoVE K12

The JoVE Math Fundamentals collection is designed to build a deep and comprehensive understanding of essential mathematics. Covering the foundations of algebra, geometry, trigonometry, and analytic reasoning, this course establishes a strong base for future studies. The collection connects core mathematical concepts with real-world practice, equipping learners to solve complex problems, master problem-solving skills, and apply abstract ideas.

math fundamentals

Solving Quadratics by Factoring and Formula

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