Simplifying Complex Expressions: (3-4i)(6i+7)-(2-3i)
This article will guide you through simplifying the complex expression (3-4i)(6i+7)-(2-3i).
Understanding Complex Numbers
Complex numbers are numbers that can be expressed in 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).
Step-by-Step Simplification
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Expand the product:
- We begin by expanding the first part of the expression, (3-4i)(6i+7), using the distributive property (also known as FOIL): (3-4i)(6i+7) = (3 * 6i) + (3 * 7) + (-4i * 6i) + (-4i * 7) = 18i + 21 - 24i² - 28i
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Simplify using i² = -1:
- Replace i² with -1: = 18i + 21 - 24(-1) - 28i = 18i + 21 + 24 - 28i
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Combine real and imaginary terms:
- Group the real terms and the imaginary terms: = (21 + 24) + (18 - 28)i = 45 - 10i
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Subtract the second complex number:
- Now, subtract the second complex number (2-3i) from the simplified result: = (45 - 10i) - (2 - 3i) = 45 - 10i - 2 + 3i
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Combine real and imaginary terms again:
- Group the real terms and the imaginary terms: = (45 - 2) + (-10 + 3)i
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Final simplification:
- Simplify the expression: = 43 - 7i
Conclusion
Therefore, the simplified form of the complex expression (3-4i)(6i+7)-(2-3i) is 43 - 7i.