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Ch. 1 - Equations and Inequalities
Chapter 2, Problem 19

In Exercises 9–20, find each product and write the result in standard form. (2 + 3i)^2

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Identify the expression to be squared: \((2 + 3i)^2\).
Apply the formula for squaring a binomial: \((a + b)^2 = a^2 + 2ab + b^2\).
Substitute \(a = 2\) and \(b = 3i\) into the formula: \((2)^2 + 2(2)(3i) + (3i)^2\).
Calculate each term separately: \(2^2\), \(2 \times 2 \times 3i\), and \((3i)^2\).
Combine the real and imaginary parts to write the result in standard form \(a + bi\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Complex Numbers

Complex numbers are numbers that have a real part and an imaginary part, expressed in the form a + bi, where a is the real part, b is the imaginary part, and i is the imaginary unit defined as the square root of -1. Understanding complex numbers is essential for performing operations such as addition, subtraction, multiplication, and division.
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Multiplication of Complex Numbers

To multiply complex numbers, you apply the distributive property (also known as the FOIL method for binomials) and combine like terms. When multiplying, remember that i^2 equals -1, which is crucial for simplifying the result. This process allows you to express the product in standard form, a + bi.
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Standard Form of Complex Numbers

The standard form of a complex number is a + bi, where a and b are real numbers. In this form, a represents the real part, and b represents the imaginary part. Writing complex numbers in standard form is important for clarity and consistency in mathematical communication, especially when performing further calculations or comparisons.
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