Make the given changes in the indicated examples of this section and then solve the resulting quadratic equations by completing the square.

In Example 3, change the coefficient of the second term from 16 to 12.

Data from Example 3

Solve 2x² + 16x − 9 = 0 by completing the square.

Therefore, the roots are

The calculator solution, using the zero feature, is shown in Fig. 7.4(a) and (b). We use the zero feature twice, since we can find only one root at a time. We see from the calculator display that the decimal approximations of the roots are 0.5277 and −8.5277.

Transcribed Image Text:

x² + 8x -1²/2- = 0 -- (8) || x² + 8x = 2/2 9 4; 42 = 16 ↓ x² + 8x + 16 12/20 + 16 = (x + 4)² = 41 x = −4+ x + 4 = ± 41 41 41 2