Graphing Equations

Link of the Day

Since I shamefully allowed both Star Wars Day and Cinco de Mayo to pass without comment, I'll make up for it with two links. First, a brief history of Cinco de Mayo explains what the holiday is as well as who celebrates it, why, and how. Second, this article about Star Wars as a religious allegory reveals that no one is sure which (if any) religion is portrayed in Lucas' famous series. Happy Cinco de Mayo, and May the Fourth be with you!

5/6 Graphing Equations

Read the following SAT test question and then select your answer. 

Always follow the Knowsys Method: Read carefully, getting information not only from the question itself but also from any charts, graphs, or figures included. Make careful note of labels and scales on all images. Identify the bottom line and copy it at the top of your scratch work. Assess your options, select the fastest way to solve the problem, and attack. Loop back to make sure you answered the question correctly.



The function y=f(x), defined for , is graphed above. For how many different values of x is f(x) = 0.2? 

First, write at the top of your scratch work # times f(x) = 0.2 = ?

Next, assess your options. You could try plugging in 0.2, but you have nothing to plug it into. You could guess, but (while that is always an option on the test) that choice will not help you during practice. Your only option is to look at the graph and count.



Make sure you pay attention to the labels on the graph. You're looking for points where f(x) = 0.2, so first draw a line at y = 0.2. Since the scale on this graph is 0.5, you need to draw a horizontal line a little less than halfway up to the first tick mark above the x-axis. Next, simply count how many times the two lines intersect.

A) None

B) One

C) Two

D) Three

E) Four

The answer is E.


On sat.collegeboard.org, 39% of responses were correct.


For more help with math, visit www.myknowsys.com!