Collecting like terms means to simplify terms in expressions in which the variables are the same. In the expression \(5a + 2b + 3a - 6b\), the terms \(5a\) and \(+ 3a\) are like terms, as are \(2b\) ...

Two of the terms involve \(x\) and two involve \(y\). Now we can combine the \(x\) terms and combine the \(y\) terms to get \(3x + 2y\).

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 ...