The graph has a vertical line of symmetry. Understanding how to substitute values into an expression is an essential skill when using graphs to estimate values of x and y.

Right-click the chart, choose "Select Data" and highlight all entries in the single column. If you use a line chart with two columns of data, each column will represent the Y axis of a separate line.

To change all data labels, click anywhere in the chart. To modify all labels on either the x or y-axis, click anywhere within the data series. To modify a single data label, click on the data label.