Skip to main content
Ch. 1 - Equations and Inequalities
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 13

Find each product and write the result in standard form. (7 - 5i)(- 2 - 3i)

검증된 단계별 안내
1
Recall that to multiply two complex numbers, you use the distributive property (also known as FOIL for binomials): multiply each term in the first complex number by each term in the second complex number.
Write the expression explicitly: \((7 - 5i)(-2 - 3i) = 7 \times (-2) + 7 \times (-3i) + (-5i) \times (-2) + (-5i) \times (-3i)\).
Calculate each product separately: \(7 \times (-2) = -14\), \(7 \times (-3i) = -21i\), \((-5i) \times (-2) = 10i\), and \((-5i) \times (-3i) = 15i^2\).
Remember that \(i^2 = -1\), so replace \$15i^2$ with \(15 \times (-1) = -15\).
Combine the real parts \((-14)\) and \((-15)\), and combine the imaginary parts \((-21i)\) and \$10i$ to write the product in standard form $a + bi$.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Complex Numbers

Complex numbers are numbers in the form a + bi, where a and b are real numbers and i is the imaginary unit with the property i² = -1. They extend the real number system and are used to represent quantities involving the square root of negative numbers.
추천 영상:
04:22
Dividing Complex Numbers

Multiplication of Complex Numbers

To multiply complex numbers, use the distributive property (FOIL method) to expand the product, then combine like terms. Remember to replace i² with -1 to simplify the expression into standard form a + bi.
추천 영상:
05:02
Multiplying Complex Numbers

Standard Form of a Complex Number

The standard form of a complex number is a + bi, where a is the real part and b is the imaginary part. Writing the product in this form means expressing the result as a sum of a real number and an imaginary number.
추천 영상:
05:02
Multiplying Complex Numbers