Simplifying Complex Expressions: (9-7i)(1+3i) - 2(3-4i)
This article will guide you through the steps of simplifying the complex expression: (9-7i)(1+3i) - 2(3-4i).
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, where i² = -1.
Simplifying the Expression
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Expand the product:
- (9-7i)(1+3i) = (9 * 1) + (9 * 3i) + (-7i * 1) + (-7i * 3i)
- = 9 + 27i - 7i - 21i²
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Simplify using i² = -1:
- = 9 + 27i - 7i + 21
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Combine real and imaginary terms:
- = (9 + 21) + (27 - 7)i
- = 30 + 20i
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Simplify the second part of the expression:
- -2(3-4i) = -6 + 8i
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Combine the simplified parts:
- (30 + 20i) + (-6 + 8i) = 24 + 28i
Final Result
Therefore, the simplified form of (9-7i)(1+3i) - 2(3-4i) is 24 + 28i.