In algebra, letters are used when numbers are not known. Algebraic terms, such as \(2s\) or \(8y\), leave the multiplication signs out. So rather than \(2 \times s\), write \(2s\), and rather than \(8 ...

Expressions like the following are called polynomials in one variable. 0, -5, 7 etc. are examples of constant polynomials. The constant polynomial 0 is also the zero polynomial. Others like 7x + 9 is ...