


Equation Solving
There are a number of algebraic terms you should know
in order to be able to talk and think about algebra.
Variable:
an unknown quantity, written as a letter. x and y are
the most commonly used letters for variables, but a variable can
be represented by any letter in the English (or even Greek) alphabet.
Variables allow you to describe general situations without specific
numbers.
Constant:
a quantity that does not change. In other words, a number.
Term:
a constant or variable and its coefficient. In an algebraic
equation, you’ll find that addition and subtraction signs often
separate terms from one another. For example, in the equation:
the left side contains four terms {3x^{3},
2x^{2}, –7x,
4} and the right side contains two terms {x, –1}.
Expression:
any combination of terms. An expression can be as simple
as a single constant term, like 5. It can also be as complicated
as the sum or difference of many terms, each of which is a combination
of constants and variables, such as {(x^{2} +
2)^{3} – 6x} ⁄ 7x^{5}.
Expressions don’t include an “equals” sign, which is what differentiates
expressions from equations. Expressions therefore cannot be solved;
they can only be simplified.
Equation:
two expressions linked by an equal sign.
