Common Core: High School - Number and Quantity : Complex Conjugate: CCSS.Math.Content.HSN-CN.A.3

Study concepts, example questions & explanations for Common Core: High School - Number and Quantity

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All Common Core: High School - Number and Quantity Resources

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Example Questions

Example Question #83 : High School: Number And Quantity

Simplify.

\displaystyle \frac{3+2i}{9-6i}

Possible Answers:

\displaystyle 3+3i

\displaystyle \frac{5+12i}{39}

\displaystyle -6+8i

\displaystyle \frac{1}{3}

Correct answer:

\displaystyle \frac{5+12i}{39}

Explanation:

\displaystyle \frac{3+2i}{9-6i}\cdot \frac{9+6i}{9+6i}

\displaystyle =\frac{\left ( 3+2i \right )\left ( 9+6i \right )}{\left ( 9-6i \right )\left ( 9+6i \right )}

\displaystyle =\frac{27+18i+18i+12i^{2}}{81+54i-54i-36i^{2}}

\displaystyle =\frac{27+36i-12}{81+36}

\displaystyle =\frac{15+36i}{117}

\displaystyle =\frac{3\left ( 5+12i \right )}{3\left ( 39 \right )}

\displaystyle =\frac{5+12i}{39}

Example Question #11 : Complex Conjugate: Ccss.Math.Content.Hsn Cn.A.3

Simplify.

\displaystyle \frac{6-4i}{-3i}

Possible Answers:

\displaystyle 6-7i

\displaystyle 6-i

\displaystyle -2i

\displaystyle \frac{4+6i}{3}

Correct answer:

\displaystyle \frac{4+6i}{3}

Explanation:

\displaystyle \frac{6-4i}{-3i}\cdot \frac{3i}{3i}

\displaystyle \frac{18i-12i^{2}}{-9i^{2}}

\displaystyle \frac{18i+12}{9}

\displaystyle \frac{12+18i}{9}

\displaystyle \frac{3\left ( 4+6i \right )}{3\left ( 3 \right )}

\displaystyle \frac{4+6i}{3}

All Common Core: High School - Number and Quantity Resources

6 Diagnostic Tests 49 Practice Tests Question of the Day Flashcards Learn by Concept
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