Subjects algebra

Complex Multiplication 0Facea

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Question: User: $(4+6i)(9-2i)$
1. **State the problem:** Multiply the complex numbers $4+6i$ and $9-2i$. 2. **Recall the formula:** To multiply two complex numbers $(a+bi)(c+di)$, use the distributive property: $$ (a+bi)(c+di) = ac + adi + bci + bdi^2 $$ Remember that $i^2 = -1$. 3. **Apply the formula:** $$ (4+6i)(9-2i) = 4 \times 9 + 4 \times (-2i) + 6i \times 9 + 6i \times (-2i) $$ 4. **Calculate each term:** $$ = 36 - 8i + 54i - 12i^2 $$ 5. **Simplify $i^2$ term:** Since $i^2 = -1$, $$ -12i^2 = -12 \times (-1) = 12 $$ 6. **Combine like terms:** $$ 36 + 12 + (-8i + 54i) = 48 + 46i $$ 7. **Final answer:** $$ (4+6i)(9-2i) = 48 + 46i $$