Solve quadratic equations by factoring

Find two numbers that multiply to the constant and add to the x coefficient.

1. Solve by factoring: x² − 7x − 18 = 0
2. Solve by factoring: x² − 15x + 56 = 0
3. Solve by factoring: x² − 9x + 20 = 0
4. Solve by factoring: x² + 3x + 2 = 0
5. Solve by factoring: x² + 2x − 48 = 0
6. Solve by factoring: x² − x = 0
7. Solve by factoring: x² − 13x + 40 = 0
8. Solve by factoring: x² − 7x = 0
9. Solve by factoring: x² − 14x + 48 = 0
10. Solve by factoring: x² − 2x − 15 = 0
11. Solve by factoring: x² + x − 72 = 0
12. Solve by factoring: x² − 7x + 10 = 0
13. Solve by factoring: x² − 9x + 18 = 0
14. Solve by factoring: x² + x − 42 = 0
15. Solve by factoring: x² − 3x + 2 = 0
16. Solve by factoring: x² + 11x + 30 = 0
17. Solve by factoring: x² − x − 6 = 0
18. Solve by factoring: x² + 11x + 28 = 0
19. Solve by factoring: x² + 11x + 24 = 0
20. Solve by factoring: x² + 8x + 12 = 0