The answer for this problem is a,c, and d
The product of a <em>complex</em> number and its conjugate is (a + i b) · (a - i b), where a and b are <em>real</em> numbers, and the result for the <em>complex</em> number 2 + i 3 is 13.
<h3>What is the multiplication of a complex number and its conjugate</h3>
Let be a <em>complex</em> number a + i b, whose conjugate is a - i b. Where a and b are <em>real</em> numbers. The product of these two numbers is:
(a + i b) · (a - i b)
Then, we proceed to obtain the result by some algebraic handling:
a · (a + i b) + (- i b) · (a + i b)
a² + i a · b - i a · b - i² b²
a² - i² b²
a² + b²
If we know that a = 2 and b = 3, then the product of the complex number and its conjugate is:
To learn more on complex numbers: brainly.com/question/10251853
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<h3>
Answer: 2x+4y+12z (choice B)</h3>
Work Shown:
x = amount of rent paid per half year
2x = amount of rent paid annually
y = amount spent on groceries per quarter
4y = amount spent on groceries annually
z = amount spent on a transit pass monthly
12z = amount spent on transit pass annually
2x+4y+12z = total amount of money spent annually