The Interpreting and finding intercepts of linear functions exercise used to appear under the Algebra I Math Mission. This exercise finds axis intercepts in various contextual word problems.
Types of Problems
There are two types of problems in this exercise:
- Find the x-intercept word problem: This problem has a word problem that is asking about when something happens. The student needs to use the information in the problem to find the x-intercept of the model of the situation.
- Find the y-intercept word problem: This problem has a word problem that is asking about an initial value. The student needs to use the information in the problem to find the y-intercept of the model of the situation.
Strategies
Being able to find the equation of a line from two points and an ability to read English and translate into mathematics would ensure success on this exercise.
- Watching the words can help to determine which problem it is. When you are looking for where things began, it is often y-intercept, when you are looking for when they happen, it is often x.
Calculator Program for TI83/84 series
This program will provide the x-intercept and y-intercept of a line by providing two points (A,B) and (C,D).
- Prompt A,B,C,D
- (D-B)/(C-A)>M
- Y-MX>B
- (Y-B)/M>X
- Disp X,B
Real-life applications
- Indicators from ETS show that the "New SAT" coming in 2015-2016 will have problems like this exercise.