1. To add fractions, you need a common denominator. Remember!

3. Example 1A: Using the Quadratic Formula Solve using the Quadratic Formula. 6x 2 + 5x – 4 = 0 6x 2 + 5x + (–4) = 0 Identify a, b, and c. Use the Quadratic Formula. Simplify. Substitute 6 for a, 5 for b, and –4 for c.

4. Solve using the Quadratic Formula. 6x 2 + 5x – 4 = 0 Write as two equations. Solve each equation.

5. Example 1B: Using the Quadratic Formula x 2 = x + 20 1x 2 + (–1x) + (–20) = 0 Write in standard form. Identify a, b, and c. Use the quadratic formula. Simplify. Substitute 1 for a, –1 for b, and –20 for c.

6. Example 1B Continued x = 5 or x = –4 Simplify. Write as two equations. Solve each equation. x 2 = x + 20

7. 1x 2 – 9x + 20 = 0 x = 5 or x = 4 Solve x 2 – 9x + 20 = 0. Show your work.

9. Check It Out! Example 5a Solve. Show your work. x 2 + 7x + 10 = 0 Method 1 Solve by graphing. y = x 2 + 7x + 10 Write the related quadratic function and graph it. The solutions are the x-intercepts, –2 and –5.

10. Check It Out! Example 5a Continued Method 2 Solve by factoring. x 2 + 7x + 10 = 0 (x + 5)(x + 2) = 0 x + 5 = 0 or x + 2 = 0 x = –5 or x = –2 Factor. Use the Zero Product Property. Solve each equation. Solve. Show your work. x 2 + 7x + 10 = 0