Khan Academy
Khan Academy: Quadratic Systems: Both Variables Are Squared
See a worked example of quadratic systems where both variables are squared. [3:33]
Khan Academy
Khan Academy: Quadratic System With No Solutions
Sal solves a system of two quadratic equations algebraically and finds the system has no solutions. He then graphs the equations to show that this is true. [6:57]
Khan Academy
Khan Academy: Quadratic Systems: Graphical Solution
Sal solves a system of a quadratic equation and a linear equation by graphing both equations and looking for their intersections, and then checks the solution algebraically. [5:44]