Multiplying Complex Numbers: (2 + 3i)(3 + 5i)
This article will guide you through the process of multiplying two complex numbers: (2 + 3i) and (3 + 5i).
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 (i.e., i² = -1).
Multiplication Process
To multiply complex numbers, we use the distributive property (also known as FOIL method) just like we do with binomial expressions in algebra.
Here's how to multiply (2 + 3i)(3 + 5i):
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Distribute:
- (2 + 3i) * (3 + 5i) = 2(3 + 5i) + 3i(3 + 5i)
-
Simplify:
- = (6 + 10i) + (9i + 15i²)
-
Substitute i² = -1:
- = (6 + 10i) + (9i - 15)
-
Combine like terms:
- = (6 - 15) + (10 + 9)i
-
Final result:
- = -9 + 19i
Therefore, the product of (2 + 3i) and (3 + 5i) is -9 + 19i.
Summary
Multiplying complex numbers involves applying the distributive property and substituting i² with -1. This process leads to a new complex number, represented in the form a + bi.