Simplifying Complex Expressions
This article will guide you through the process of simplifying the complex expression: (-1-7i)(2+i)+(8-2i).
Understanding Complex Numbers
Before we begin, let's quickly recap what complex numbers are:
- Complex numbers are numbers that can be expressed in the form a + bi, where:
- a and b are real numbers
- i is the imaginary unit, defined as the square root of -1 (i² = -1).
Simplifying the Expression
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Expand the product:
We start by expanding the product of the two complex numbers using the distributive property (FOIL method):
(-1 - 7i)(2 + i) = (-1)(2) + (-1)(i) + (-7i)(2) + (-7i)(i) = -2 - i - 14i - 7i²
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Substitute i² with -1:
Since i² = -1, we can substitute it into the expression:
-2 - i - 14i - 7i² = -2 - i - 14i - 7(-1)
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Combine real and imaginary terms:
Combine the real terms and the imaginary terms separately:
-2 + 7 - i - 14i = 5 - 15i
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Add the remaining complex number:
Finally, add the remaining complex number (8 - 2i):
5 - 15i + (8 - 2i) = 5 + 8 - 15i - 2i = 13 - 17i
Conclusion
The simplified form of the complex expression (-1 - 7i)(2 + i) + (8 - 2i) is 13 - 17i.