Repeat the Related Problem from Example 9-5 using the TI-89.Example 9-58I1 + 4I2 + I3 = 72...

Repeat the Related Problem from Example 9-5 using the TI-89.

Example 9-5

8I1 + 4I2 + I3 = 7

2 I1 − 5I2 + 6I3 = 3

3 I1 + 3I2 − 2I3 =−5

Press the 2nd key, then SIMULT to enter the number of equations as shown in Figure 9-2.

Figure 9-2

After you enter 3 and press ENTER, the first equation screen comes up. Enter the coefficients 8, 4, 1 and the constant 7 by pressing each number key followed by the ENTER key, which results in the screen shown in Figure 9-3(a). After you enter the last number and press ENTER, the second equation screen appears. Enter the coefficients 2, −5, 6 and the constant 3 as shown in Figure 9-3(b) (A negative value is entered by first pressing the (−) key.). Finally, enter the coefficients of the third equation (3, 3, −2) and the constant −5 as shown in Figure 9-3(c).

Figure 9-3

Selecting SOLVE, which is the F5 key, produces the results displayed in Figure 9-5. XI is I1, X2 is I2, and X3 is I3.

Figure 9-5