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Finding X-intercepts of a Graph [TI-84 Instructions]

I typed up this set of instructions for finding the x-intercepts of a graph using the TI-84 for my Algebra 2 students to fill in and glue in their interactive notebooks.

I also created a similar set of instructions for finding the y-intercept of a graph using the TI-84 calculator.

Steps for Finding the X-Intercepts of Graph Using the TI-84

  • Enter the equation into Y1
  • Press GRAPH
  • Open the Calculate Function (2ND TRACE)
  • Select Option 2: ZERO
  • Move the blinking cursor to the left of where the graph crosses the x-axis
  • Press ENTER
  • Move the blinking cursor to the right of where the graph crosses the x-axis
  • Press ENTER
  • Move the blinking cursor as close as possible to where the graph crosses the x-axis
  • Press ENTER
  • Record the x-intercept
  • Repeat this process if the graph has more than one x-intercept

Another thing that throws my students off is the fact that they are rarely asked to find the x-intercepts of a graph on their end-of-instruction exam.  Instead, they will be asked to find the roots, solutions, or zeros of an equation.  I really try to drive home the fact that anytime they are asked for roots, solutions, or zeros, they are really just being asked to find the x-intercept.

finding the x-intercept of a graph with ti-84 interactive notebook page.

I told my students to draw a box around this fact, star it, add exclamation points, or anything that would make it stand out in their notes.  They noted that the way I had boxed it in on mine looked like the state of Oklahoma.  I joked that I had done that on purpose because the state of Oklahoma was requiring them to know this fact.

My students really struggled with the left bound and right bound instructions, so I shared with them a tip I learned from @druinok.  She has her students place the cursor as close to the point as possible and then click the left arrow a few times for left bound and the right arrow a few times for right bound.  My students thought this was the best trick ever.  It really cut down on the mistakes they were making.