Math Problem Statement

Perform the indicated operation & simplify. Express the answer in terms of i (as a complex number): (4 - 2i)(8 + 7i) = ?

Solution

To solve (42i)(8+7i)(4 - 2i)(8 + 7i), we will expand and simplify using the distributive property and the fact that i2=1i^2 = -1.

Step 1: Expand the expression

(42i)(8+7i)=4(8)+4(7i)2i(8)2i(7i)(4 - 2i)(8 + 7i) = 4(8) + 4(7i) - 2i(8) - 2i(7i)

Simplify each term: =32+28i16i14i2= 32 + 28i - 16i - 14i^2

Step 2: Simplify further

Combine the real and imaginary parts: 32+(28i16i)14i2=32+12i14i232 + (28i - 16i) - 14i^2 = 32 + 12i - 14i^2

Since i2=1i^2 = -1, substitute 1-1 for i2i^2: =32+12i14(1)= 32 + 12i - 14(-1)

=32+12i+14= 32 + 12i + 14

Step 3: Final result

Combine the real parts: =46+12i= 46 + 12i

Thus, the simplified result is: 46+12i\boxed{46 + 12i}

Let me know if you want further clarifications! Here are some related questions:

  1. How do you multiply two complex numbers geometrically?
  2. What are the rules for simplifying complex numbers involving i2i^2?
  3. Can this be represented in polar form? How would you do it?
  4. How does the distributive property apply to complex numbers?
  5. What are some practical applications of multiplying complex numbers?

Tip: Always check for i2=1i^2 = -1 during simplifications to avoid errors in handling imaginary components!

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Distributive Property
Simplification

Formulas

(a + bi)(c + di) = (ac - bd) + (ad + bc)i

Theorems

i^2 = -1

Suitable Grade Level

Grades 10-12