Khan Academy
Quadratic Formula (Proof)
This exciting video removes all of the mystery from the quadratic formula. By watching it, learners gain a deeper understanding of the formula and the process of completing the square. Sal shows step-by-step proof of how to get to the...
Khan Academy
Identifying a Hyperbola From an Equation, Conic Sections, Algebra II
In this video, Sal shows again how to write an equation of a conic section in standard form and identify the conic section it represents. This time, his example is of a hyperbola (not centered at the origin), which he also graphs.
Khan Academy
Identifying an Ellipse From Equation, Conic Sections, Algebra II
After watching this video, you should be able to write an equation for a conic section in standard form and identify the conic section from its equation. In an example problem, Sal reviews how to complete the square and graph an ellipse...
Khan Academy
Identifying Circles and Parabolas from Equations, Conic Sections, Algebra II
This is the last of three well-done videos on identifying and graphing conic sections from an equation. Here, Sal shows how to graph a circle not centered at the origin and a parabola that opens downward.
Khan Academy
Identifying a Hyperbola from an Equation, Conic Sections, Algebra II
In this video, Sal shows again how to write an equation of a conic section in standard form and identify the conic section it represents. This time, his example is of a hyperbola (not centered at the origin), which he also graphs.
Khan Academy
Identifying an Ellipse from Equation, Conic Sections, Algebra II
After watching this video, you should be able to write an equation of a conic section in standard form and identify the conic section from its equation. In an example problem, Sal reviews how to complete the square and graph an ellipse...
Khan Academy
Identifying Circles and Parabolas from Equations, Conic Sections, Algebra II
This is the last of three well-done videos on identifying and graphing conic sections from an equation. Here, Sal graphs a circle that is not centered at the origin and a parabola that opens downward.
Khan Academy
Solving Quadratic Equations by Completing the Square, Algebra II
"The neat thing about completing the square is that it will always work," Sal explains, "no matter how crazy the problem is." This video provides a basic overview of how to complete the square and provides a good background for both...
Curated OER
Completing the Square
The instructor discusses how to solve a quadratic equation by completing the square. The verbal explanation is fairly complete, but the writing of the steps is rather vague.