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# Algebra Homework Help : Algebraic Terms and Definitions

 Preparation Just what you need to know !

## What are Some of the Commonly Used Terms in Algebra?

In algebra, the letter that stands for an unknown number is called a variable. The variables in 8x2y3 are x and y.

The number that multiplies a variable or variables is called the coefficient. It is usually written in front of the variable or variables. The coefficient in 9yz4 is 9. When the coefficient is 1, it is typically not written (i.e., 1yz4 = yz4 and 1a3 = a3).

The power to which a variable is raised is called the exponent. The exponent in 7a5 is 5. When the exponent is 1, it is typically not written (i.e., 6y1z4 = 6yz4). Any variable or number raised to the power zero gives one (i.e., x0 = 1).

Any number or variable or product of numbers and variables is called a monomial. Each of the following is an example of a monomial :
5, −7, x, y, 6xyz, −9yz4, 2.3a3

A monomial or the sum of two or more monomials is called a polynomial. Each of the following is an example of a polynomial :
6xyz, 5a3 − 21, 4x2 − 9y2, 2x + 3y + 4z, 5x2 + 6x + 7

Each monomial that makes up a polynomial is referred to as a term of the polynomial.

A polynomial that has two (unlike) terms is called a binomial (e.g., 6a3 − 23 and 5x2 + 18y2).

A polynomial that has three (unlike) terms is called a trinomial. (e.g., 3x + 5y + 7z and 6x2 + 9x + 12).

Like terms are those that have exactly the same variables and exponents. They may differ only in their coefficients. Importantly, the only algebraic terms that can be combined (added or subtracted) are like terms. Thus, 7y2z and −9y2z are like terms, but x2y and xy2 are unlike terms.

A collection of algebraic terms connected by mathematical symbols is called an algebraic expression, and an algebraic expression whose parts are not separated by + or − signs is called a term. Thus, 5x2 + 3xy + 2y2 is an algebraic expression with three terms 5x2, 3xy and 2y2.

A statement that two algebraic expressions are equal is called an equation. Each of the following is an example of an equation :
2x + 7 = 5x − 8
x2 + 5x + 6 = 0

An equation where the highest power to which a variable is raised is one is called a linear equation. Thus, 3x − 7 = 7x + 3 is an example of a linear equation.

An equation where the highest power to which a variable is raised is two is called a quadratic equation. Thus 3x2 + 6x + 10 = 0 is an example of a quadratic equation.

An equation where the highest power to which a variable is raised is three is called a cubic equation. Thus 7x3 + 8x + 9 = 0 is an example of a cubic equation.

An equation where the highest power to which a variable is raised is four is called a quartic equation. Thus 7x4 + 15x3 + 8x2 + 9 = 0 is an example of a quartic equation.

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