Here is a quick list of frequently used commands for mathematics in Latex.

All commands are in math mode, i.e. enclosed within either dollar signs or "\[ ... \]."

For all real numbers A, B and for when C does NOT equal 0, the equations:

A = B and AC = BC are equivalent to one another.

Each side can be multiplied by the same NONZERO number without changing the solution set.

For all real numbers A, B and C, the equations:

A = B and A + C = B + C are equivalent to one another.

The same number may be added to each side of an equation without altering the solution set.

**Equations and Expressions are closely related.**

The primary difference between the two is an equals sign. An "equation" has a left side, a right side and an equals sign separating the sides. An "expression," by contrast, doesn't have any "sides" and is simply what the name suggests: An algebraic "expression." Though sometimes it is possible to combine like terms, we are generally not expected to "do" or "solve" anything regarding expressions.

For example:

3x - 7 = 2

This is an **EQUATION**, because it has a left side, a right side, and an = sign separating the two.

3x - 7

This is an **EXPRESSION**, because there are no "sides" and no = sign.