As stated on the Common Core State Standards initiative website(http://www.corestandards.org/Math/Content/HSA/introduction/)
Algebra I instructional time should focus on two main areas: Equations and Inequalities and Connections to Functions and Modeling. The study of Equations and Inequalities include writing an equation based on a context, and representing the situation using multiple representations. Students will solve equations, as well as graph them by hand and on a graphing calculator. Inequalities will be solved by reasoning about the properties of inequality. Many, but not all, of the properties of equality continue to hold for inequalities and can be useful in solving them.
The study of Connections to Functions and Modeling include recognizing that expressions can define functions and equivalent expressions define the same function. Asking when two functions have the same value for the same input leads to an equation; graphing the two functions allos for finding approximate solutions of the equation. Converting a verbal description to an equation, inequality, or system of these is an essential skill in modeling.