Simplifying Complex Expressions: A Step-by-Step Guide
This article will walk you through the process of simplifying the complex expression: (5 + 2yi)(4 - 3i) - (5 - 2yi)(4 - 3i)
Understanding Complex Numbers
Complex numbers are numbers of the form a + bi, where 'a' and 'b' are real numbers and 'i' is the imaginary unit, defined as the square root of -1 (i² = -1).
Simplifying the Expression
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Expand the products:
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(5 + 2yi)(4 - 3i):
- Use the distributive property (FOIL method):
- (5 * 4) + (5 * -3i) + (2yi * 4) + (2yi * -3i)
- Simplify: 20 - 15i + 8yi - 6i²
- Substitute i² with -1: 20 - 15i + 8yi + 6 = 26 - 15i + 8yi
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(5 - 2yi)(4 - 3i):
- Follow the same process:
- (5 * 4) + (5 * -3i) + (-2yi * 4) + (-2yi * -3i)
- Simplify: 20 - 15i - 8yi + 6i²
- Substitute i² with -1: 20 - 15i - 8yi - 6 = 14 - 15i - 8yi
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Subtract the expanded expressions:
- (26 - 15i + 8yi) - (14 - 15i - 8yi)
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Combine like terms:
- (26 - 14) + (-15i + 15i) + (8yi + 8yi) = 12 + 16yi
Final Result
The simplified expression is 12 + 16yi.