, an expression is a set of one or more terms
. For instance, in the equation
7x - 2y + 3z = 3x + 7y - 2z
7x - 2y + 3z is an expression, as is 3x + 7y - 2z.
However, 7x - 2y + 3z = 3x + 7y - 2z is not in and of itself an expression.
These expressions are given diffrent names depending on the number of terms involved.
An expression with one term
, like 7x alone, is called a monomial
An expression with two terms
, like 3x + 4y, is called a binomial
An expression with three terms
, like 5x + 8z - 3xz, is called a trinomial