Texas Instruments TI-92 Getting Started page 20

Remember that when an equation has more than one x-intercept, it may be necessary to change the viewing
rectangle a few times to locate all of them.
The TI-92 has a solve( function. To use this function, you must be in the Home screen. To use the solve( function,
press S O L V E ( 24 X ∧ 3 – 35 X + 17 = 0 , X) ENTER. The TI-92 displays the value of the zero (Figure 5.59).
Note that any letter could have been used for the variable. This is the reason that you must indicate to the TI-92 that
the variable being used is X.
Technology Tip: To solve an equation like 24x
36x + 17 = 0, and proceed as above. However, the solve( function does not require that the function be in standard
form. You may also graph the two functions y = 24x
intersection.
5.3.3 Solving Systems by Graphing: The solutions to a system of equations correspond to the points of intersection
of their graphs (Figure 5.60). For example, to solve the system y = x
them together. Then use zoom and trace or the intersection option in the F5[Math] menu, to locate their point of
intersection, approximately (–2.17, 7.25).
If you do not use the Intersection option, you must judge whether the two current y-coordinates are sufficiently
close for x = –2.17 or whether you should continue to zoom and trace to improve the approximation.
The solutions of the system of two equations y = x
3
the single equation x + 3x
3 2
+ x + 3 and find its x-intercepts to solve the system or use the solve( function.
x +2x
5.3.4 Solving Inequalities by Graphing: Consider the inequality
3
y = −
the two functions
1
2
inequality is true when the graph of
x ≤ , or (–∞, 2].
solution is the half-line
2 0
Graphing Technology Guide: TI-92
Figure 5.59: solve( function
3
+ 17 = 36x, you may first transform it into standard form, 24x
3
Figure 5.60: Graph of y = x
3
+ 3x
2 2
– 2x – 1= x – 3x – 4, which simplifies to x
x
and y = x – 4 (Figure 5.61). First locate their point of intersection, at x = 2. The
3 x
y = −
lies above the graph of y = x – 4 , and that occurs when x < 2. So the
1
2
2
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+ 17 and y = 36x, then zoom and trace to locate their point of
3 2
+ 3x – 2x – 1 and y = x
3 2
+ 3x – 2x – 1 and y = x
2 2
– 2x – 1 and y = x – 3x – 4 correspond to the solutions of
3 2
+ 2x + x + 3 = 0. So you may also graph y =
3 x
− ≥ − . To solve it with your TI-92, graph
1 x 4
2
2
– 3x – 4 , first graph
2
– 3x – 4
3
–