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

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 \(2b\) ...

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 ...