Intercepts from a graph

The  exercise appears under the 8th Grade Math Mission. This exercise finds axis intercepts in various situations.

Types of Problems
There are three types of problems in this exercise:


 * 1) Determine the y-intercept with graph: This problem provides an equation and a graph. The student is asked to find the y-coordinate of the y-intercept.Lfi1.png
 * 2) Determine the x-intercept with graph: This problem provides an equation and a graph. The student is asked to find the x-coordinate of the x-intercept.Lfi2.png
 * 3) Use the chart to find the intercept: This problem provides a chart with some values of a linear function. The student is asked to find an intercept based on the information from the chart.Lfi3.png

Strategies
An ability to interpret graphs and find linear equations from given information would ensure success on this exercise.
 * 1) To increase speed, the graphs can sometimes share their intercepts without having to actually solve anything. One can just see it.
 * 2) On the Use chart to find the intercept the x-intercept is located between two of the points in the chart. Taking the average of two of the x's will give the correct answer. The y-intercept can be found by continuing the pattern to get a zero for the x.
 * 3) The equations are provided with the graphs because occasionally the answers will be fractions.

Real-life applications

 * 1) Problems like this occur on SATs and other standardized tests.
 * 2) Linear models are common in business and the sciences and the x-intercept often provides information about the model.
 * 3) Information collected in the sciences often takes the form of charts and models need to be created from these charts of information.