The Rectangular Coordinate Systems and Graphs · Exercise 60

Use your graphing calculator to input the linear graphs in the Y= graph menu.

After graphing it, use the 2^nd CALC button and 2:zero button, hit ENTER. At the lower part of the screen you will see “left bound?” and a blinking cursor on the graph of the line. Move this cursor to the left of the x-intercept, hit ENTER. Now it says “right bound?” Move the cursor to the right of the x-intercept, hit ENTER. Now it says “guess?” Move your cursor to the left somewhere in between the left and right bound near the x-intercept. Hit ENTER. At the bottom of your screen it will display the coordinates of the x-intercept or the “zero” to the y-value. Use this to find the x-intercept.

Note: With linear/straight line functions the zero is not really a “guess,” but it is necessary to enter a “guess” so it will search and find the exact x-intercept between your right and left boundaries. With other types of functions (more than one x-intercept), they may be irrational numbers so “guess” is more appropriate to give it the correct limits to find a very close approximation between the left and right boundaries.

${\text{Y}}_1=\frac{3x+5}{4}$ Round your answer to the nearest thousandth.

OpenStax, Algebra and Trigonometry 2e · §2.1 The Rectangular Coordinate Systems and Graphs · Exercise 60