Khan Academy

Understanding the quadratic formula (K-A)

Using the quadratic formula (K-A)

Using the quadratic formula: number of solutions (K-A)

Worked example: quadratic formula (example 2) (K-A)

Worked example: quadratic formula (K-A)

Worked example: quadratic formula (negative coefficients) (K-A)

Intro to parabola transformations (K-A)

Scaling & reflecting parabolas (K-A)

Shifting parabolas (K-A)

Classifying numbers: rational & irrational (K-A)

Intro to rational & irrational numbers (K-A)

Proof: √2 is irrational (K-A)

Proof: square roots of prime numbers are irrational (K-A)

Proof: there's an irrational number between any two rational numbers (K-A)

Proof: product of rational & irrational is irrational (K-A)

Proof: sum & product of two rationals is rational (K-A)

Proof: sum of rational & irrational is irrational (K-A)

Sums and products of irrational numbers (K-A)

Worked example: rational vs. irrational expressions (K-A)

Worked example: rational vs. irrational expressions (unknowns) (K-A)

Appropriate units (K-A)

Appropriate units-video (K-A)

Same rate with different units (K-A)

Adding and subtracting functions (K-A)

Adding functions (K-A)