(7-3i)^2

2 min read Jun 16, 2024
(7-3i)^2

Expanding (7-3i)^2

This article will guide you through the steps of expanding the expression (7-3i)^2.

Understanding Complex Numbers

Before we start, let's understand what complex numbers are. A complex number is a number that can be expressed in the form a + bi, where 'a' and 'b' are real numbers and 'i' is the imaginary unit, defined as i^2 = -1.

Expanding the Expression

To expand (7-3i)^2, we can use the formula (a - b)^2 = a^2 - 2ab + b^2. Here's how it works:

  1. Identify 'a' and 'b': In this case, a = 7 and b = 3i.

  2. Substitute the values: (7-3i)^2 = 7^2 - 2(7)(3i) + (3i)^2

  3. Simplify:

    • 7^2 = 49
    • 2(7)(3i) = 42i
    • (3i)^2 = 9i^2 = 9(-1) = -9
  4. Combine the terms: 49 - 42i - 9

  5. Final answer: (7-3i)^2 = 40 - 42i

Conclusion

By using the formula for expanding a binomial squared, we have successfully expanded (7-3i)^2 to get 40 - 42i. This process demonstrates how complex numbers can be manipulated and simplified through algebraic operations.

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