Hi this is Rob. I will show you how to find
the X and Y intercepts of a function using the graphing feature of the TI 84 Plus CE
Calculator. We are going to use the polynomial equation
of x squared minus x minus 6. The first thing we need to do is graph this
equation. If you need more help on how to use the graphing feature of the calculator,
please see my video: How to Graph a Polynomial Function (Equation) on the TI 84 Plus CE.
I will put a link in the description below. OK, let’s get started. Press the y=key
on the top left of the calculator, here. Enter X, located on this key, then press this exponent
key, it moves the cursor to the exponent position. Enter 2. To move the cursor out of the exponent
position, press the right arrow key here. Then enter the rest of the equation. Minus
X, minus 6. Now press the Graph key located in the upper right, here. You should get this graph. if you don’t
get this graph you may need to reset your graphing window to the standard view. To reset
your graphing window, press the Zoom button here on top. Go down to number 6: ZStandard,
which stands for Zoom Standard. Press the Enter key. Now you can do a visual and see that the graph
crosses the x axis at negative 2 and positive 3. Those would be our x intercepts, but we
want to get a confirmation from the calculator. So next step is to press the 2nd key here,
then the trace key here. This brings up this Calculate window. Go to number 2: zero. Press
enter. You see the blinking cursor on the graph. On the bottom of the screen it is asking
for a Left Bound. We will confirm the x intercept at x equals negative two. So we want to set
a left bound left of x equals negative 2. Using the left arrow key, move the cursor
left of x equals negative two. That is good. Anywhere to the left of the x axis of negative
2. Press the enter key. Now the calculator is asking for a right bound. Move the cursor
using the right arrow key to the right of x equals negative 2. OK, right there is good.
Press the enter key. Now the calculator is asking for a guess of the value of the x intercept
within those bounds. Skip, this step and just press the enter button. And at the bottom
of the screen we see our answer. One of the x intercepts is at x=negative 2, y equals
0, or (-2,0). To find the other x intercept we will repeat
the steps. Press 2nd, trace. Go to number 2, zero. Press enter. On the bottom of the
screen it says Left Bound. With the right arrow key, move the cursor to the left of
where we think the other x intercept is located at x=3. Right there is ok. Press enter.
Now the calculator is asking for the Right Bound. Move the right arrow key until the
cursor is just to the right of x=3. Right there is good. Press enter. Now the calculator
says Guess, we skip that and press the enter key again. And there on the bottom of the
screen it says x=3 and y=0, that is the other x intercept. Now I am going to show you an easy way to
find the y intercept. Press the 2nd key then the trace key. This Calculate window appears.
Select 1:value. Press enter. The intercept occurs when x equals zero, so on the bottom
of the screen, type a zero after x=. Then press enter. And at the bottom of the screen
there is our y intercept at y equals negative 6. OK, that’s it. That is how to find the X
and Y intercepts of a function using the graphing feature of the TI 84 Plus CE Calculator. If you like this video please give it a thumbs
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