Introduction To Solver on the TI-86

This page demonstrates using the TI-86 (or TI-85) calculator to solve the problem given in Chapter 2, Section 0, Example 3 of the Precalculus textbook. For that example, the textbook shows a screen image from a TI-86 to illustrate using the "solver" button to do the problem, Solve 3-[5.4+2(4.3–x)]=2–(0.3x–0.8) Note that the screen image does not tell us how to arrive at the solution. Rather, the screen image is the last screen in the process of obtaining a solution. This sequence of screen images is meant to show the steps needed to arrive at the screen image given in the text.

It is possible to start this sequence with Figure 6. Figures 1 through 5 are presented here merely to let you know what is on the calculator before we actually start working on the problem.

Figure 1 We will be using the "SOLVER" feature of the calculator. This feature works with equations that have been stored in the calculator. We will use the MEM operation to inspect the already existing equations on the particular calcualtor used to generate these figures.
We start by opening the MEM menu, as shown in Figure 1. On the TI-86, this is done by pressing the keys. (On the TI-85 use the keys, and the resulting menu will only have the first three options at the bottom of the screen.)
Figure 2 We press the to move to the DELETE menu. We do not really want to delete anything. Rather, we just want to see the names of the equations that already exist on this calculator. The menu options at the bottom of the screen do not show the desired value. Therefore, we press the key to see additional options. The result is shown at the bottom of Figure 3.

Figure 3 The third option, EQU, at the bottom of Figure 3 will allow us to manage the equations that have been stored in this calculator. We select this option by pressing the key.

Figure 4 Figure 4 shows the display of the names of the equations that exist on this calculator. If we wanted to delete any of these we would move the highlight (the small arrow at the left of the screen) to point to the item that we want to delete, and then we sould press the ENTER key. In our pesent situation we did not want to delete any equations, we merely wanted to see the list of equations. Therefore we will press the key to leave the memory management system.

Figure 5 Having returned to the blank screen, for purposes of our demonstration, we will store the value 5.236 into the variable x. We do this via the key strokes.

At this point we have checked out the equations that are currently defined on the calculator, and we have stored a specific value, 5.236, into the variable x. Now let us look at the SOLVER feature on the calculator.

Figure 6 We start SOLVER by pressing the keys. A new screen, the equation entry editor screen, opens, as shown in Figure 6. Note that the options at the bottom of Figure 6 are merely the names of the equations that are currently defined and named on this calculator. We saw these names back in Figure 4.
Also, note that on a calculator that has previously used the SOLVER feature there may be a current equation assigned to eqn. If that is true, then we can simply press the CLEAR key to start fresh, as in Figure 6.

Figure 7 Here we start typing the equation into the calculator. Figure 7 shows the left side of the equation. Notice that we use parentheses, not the square brackets that are part of the original problem. Although we have reached the right side of the screen in Figure 7 we will keep typeing the equation.

Figure 8 The = sign in the equation requires us to use the key sequence. Figure 8 shows the remainder of the equation. At this point we have input the entire equation. We press the key to move ahead with the process.

Figure 9 Figure 9 shows the main SOLVER screen. Note that we have not solved the problem at this point. In fact, the value of x is exactly the value that we stored in x back in Figure 5. One thing that Figure 9 does not indicate is that the cursor is located on the "5" of "5.236". If we press the key to perform menu option 5, SOLVE, the calculator will attempt to find a solution for x, the value indicated by the cursor location, between the low and high bounds.

Figure 10 Finally, in Figure 10, we see the screen image given in the textbook. The calculator has SOLVED the equation, determining that the appropriate value for x is 6, and that the difference between the "left side of the equation" and the "right side of the equation" is 0.

Figure 1	We will be using the "SOLVER" feature of the calculator. This feature works with equations that have been stored in the calculator. We will use the MEM operation to inspect the already existing equations on the particular calcualtor used to generate these figures. We start by opening the MEM menu, as shown in Figure 1. On the TI-86, this is done by pressing the keys. (On the TI-85 use the keys, and the resulting menu will only have the first three options at the bottom of the screen.)
Figure 2	We press the to move to the DELETE menu. We do not really want to delete anything. Rather, we just want to see the names of the equations that already exist on this calculator. The menu options at the bottom of the screen do not show the desired value. Therefore, we press the key to see additional options. The result is shown at the bottom of Figure 3.
Figure 3	The third option, EQU, at the bottom of Figure 3 will allow us to manage the equations that have been stored in this calculator. We select this option by pressing the key.
Figure 4	Figure 4 shows the display of the names of the equations that exist on this calculator. If we wanted to delete any of these we would move the highlight (the small arrow at the left of the screen) to point to the item that we want to delete, and then we sould press the ENTER key. In our pesent situation we did not want to delete any equations, we merely wanted to see the list of equations. Therefore we will press the key to leave the memory management system.
Figure 5	Having returned to the blank screen, for purposes of our demonstration, we will store the value 5.236 into the variable x. We do this via the key strokes.

Figure 6	We start SOLVER by pressing the keys. A new screen, the equation entry editor screen, opens, as shown in Figure 6. Note that the options at the bottom of Figure 6 are merely the names of the equations that are currently defined and named on this calculator. We saw these names back in Figure 4. Also, note that on a calculator that has previously used the SOLVER feature there may be a current equation assigned to eqn. If that is true, then we can simply press the CLEAR key to start fresh, as in Figure 6.
Figure 7	Here we start typing the equation into the calculator. Figure 7 shows the left side of the equation. Notice that we use parentheses, not the square brackets that are part of the original problem. Although we have reached the right side of the screen in Figure 7 we will keep typeing the equation.
Figure 8	The = sign in the equation requires us to use the key sequence. Figure 8 shows the remainder of the equation. At this point we have input the entire equation. We press the key to move ahead with the process.
Figure 9	Figure 9 shows the main SOLVER screen. Note that we have not solved the problem at this point. In fact, the value of x is exactly the value that we stored in x back in Figure 5. One thing that Figure 9 does not indicate is that the cursor is located on the "5" of "5.236". If we press the key to perform menu option 5, SOLVE, the calculator will attempt to find a solution for x, the value indicated by the cursor location, between the low and high bounds.
Figure 10	Finally, in Figure 10, we see the screen image given in the textbook. The calculator has SOLVED the equation, determining that the appropriate value for x is 6, and that the difference between the "left side of the equation" and the "right side of the equation" is 0.