Transcription: Let's talk about algebraic expressions. These are some algebraic expressions. 5x, 2x-3, and this fraction. Now algebraic expressions involve variables, constants, and operations. Variables are nothing more than the letters that are used in the expressions. They're called variables because their value changes from problem to problem. In fact, this is a variable expression, even though 5 itself, if it were standard, standing alone is a constant involved with a variable, this is a variable term. Now the reason that it's a variable term is because if x is a variable then 5 times x, you see, is a v ...