# Equation

mathematical statement that asserts the equality of two expressions

A mathematical equation is an expression containing two mathematical objects connected by an equals sign (=) . The equals sign says that both sides are exactly equal, or of the same value. An equation can be as simple as x=0, or as complex as $4(3y^{99})+76=42+3x$ or harder.

There are two kinds of mathematical equations:

• The kind of equation that is either true or false; these are also called identities. For example:
$2\cdot (x+4)=2x+8\rightarrow {\text{true}}$ • The kind of equation that is only true for certain values of the variable(s). The equation is only true if the variable(s) have that value. For example:
$2\cdot x=8\rightarrow x=4$ The second kind is often used to solve problems in which finding the value of some variables is involved. For example, if

$2x=8,\,x={\frac {8}{2}}=4.$ The second kind of equation is used in algebra. For example, to solve the equation 2x = 8 for x, one would follow an algebraic rule to find that x = 4.

## Types of equations

Equations can be classified by the types of operations and quantities involved. For example: