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Recap: Imaginary Numbers

Part of the Quadratics & Complex Numbers section of Coddy's Algebra 2 journey. Lesson 21 of 51.

Challenge

Simplify √(-36) - √(-81) to a single multiple of i.

Try it yourself

sqrt(-36) - sqrt(-81)

Simplify the expression

All lessons in Quadratics & Complex Numbers

1The Vertex

The Axis of Symmetry The Vertex Point Maximum or Minimum Drawing from Standard Form Recap: The Vertex

4Imaginary Numbers

Meet i Roots of Negatives Not a Perfect Square Powers of iRecap: Imaginary Numbers

7The Discriminant

Computing It Three Kinds of Answers Reading the Sign Recap: The Discriminant

10Final Challenges

Final: Square It Away Final: The Peak Final: Divide It Final: No Real Roots Final: Where They Meet

2Completing the Square

Perfect Square Trinomials The Missing Number Completing the Square Irrational Answers When a Is Not 1 Recap: Completing the Square

5Complex Arithmetic

Adding and Subtracting Multiplying The Conjugate Dividing A Pure Imaginary Bottom Recap: Complex Arithmetic

8Lines Meet Parabolas

Two Crossings Just Touching No Meeting A Circle and a Line Recap: Lines and Parabolas

3Vertex Form by Algebra

From Standard to Vertex Odd Middle Terms A Leading Number Opening Down Recap: Vertex Form

6Complex Solutions

Squares Equal to Negatives A Shifted Square The Formula Goes Complex Fractions in the Answer Recap: Complex Solutions

9Quadratic Models

The Highest Point Back to the Ground The Biggest Area Price and Revenue Recap: Models