I understand how to solve these by factoring them but I am having trouble understanding how to use the quadratic equation. If you know how to solve a quadratic equation please help me. We are not allowed to solve them by factoring them. Thanks!
1. x^2 - 4x - 5 = 0
2. z^2 - 2z - 15 = 0
3. y^2 = 2y + 3
4. r^2 = 5 - 4r
Once again, thanks for the help!