1. Complex Numbers EQ: How do we multiply complex numbers?
M2 Unit 1A: Day 4

2. As a review…remember the distributive property and FOIL.
Multiply.
2(3x–5)
(x+3)(2x-4)
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We can sometimes multiply complex numbers using the Distributive Property…
Ex: Simplify. Write expression in standard form.
5( 2 + 6i ) ( 6 + 3i ) i i
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4. You Try: Simplify. Write expression in standard form.
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Remember…
Simplify. Write the expression in standard form.
3i ( 7 + i )
2i ( 5 + i )
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6. You Try: Simplify. Write expression in simplest form.
6i( 4 + 2i )
8i( 2 – 7i)
i( i + 4 )
2i( -3 – 10i )
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7. Now, let’s use FOIL to multiply 2 complex numbers….
Ex: Write the expression as a complex number in standard form.
(8 – 2i)(-6 + 5i)
(-3 + i)(8 + 5i)
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(4 + 3i)(4 – 3i)
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You Try: Write the expression as a complex number in standard form.
(-5 + i)(2 – 7i)
(3 – 2i)(-5 – 9i)
(-3 + 2i)(-3 – 2i)
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10. These problems have multiple steps:
18. (-4 + 5i)(1 – 4i) + (6 + 2i)
You Try.
19. -(2 + 5i) + (5 – 3i)(4 + i)
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Assignment
Pg 13 (# even)
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