College

Multiply and simplify the product: [tex](8-5i)^2[/tex]

Select the product:

A. 39
B. 89
C. 39 - 80i
D. [tex]89 - 80i[/tex]

Answer :

To solve [tex]\((8 - 5i)^2\)[/tex] and find the product in the form [tex]\(a + bi\)[/tex], follow these steps:

1. Expand the Expression:

Start by using the formula for squaring a binomial:
[tex]\((a - b)^2 = a^2 - 2ab + b^2\)[/tex]. Here, you apply the formula as:
[tex]\((8 - 5i)^2 = (8)^2 - 2 \times 8 \times 5i + (5i)^2\)[/tex].

2. Calculate Each Part:

- Square the Real Part (8):
[tex]\(8^2 = 64\)[/tex].

- Calculate the Imaginary Part Coefficient:
[tex]\(-2 \times 8 \times 5i = -80i\)[/tex].

- Square the Imaginary Part (5i):
[tex]\((5i)^2 = 25(i^2)\)[/tex].

Since [tex]\(i^2 = -1\)[/tex], it follows that [tex]\(25(i^2) = 25 \times -1 = -25\)[/tex].

3. Combine the Results:

Sum all the calculated parts:
[tex]\[
64 + (-25) + (-80i) = 39 - 80i
\][/tex]

4. Select the Product:

The calculated expression is [tex]\(39 - 80i\)[/tex], which matches the option [tex]\(\boxed{39 - 80i}\)[/tex].