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Ch. 1 - Equations and Inequalities
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
2장, 문제 107

Work each problem. Show that -3+4i is a solution of the equation x²+6x+25=0.

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1
Start by substituting the complex number \(x = -3 + 4i\) into the quadratic equation \(x^2 + 6x + 25 = 0\).
Calculate \(x^2\) by squaring \(-3 + 4i\). Use the formula \((a + bi)^2 = a^2 + 2abi + (bi)^2\) where \(a = -3\) and \(b = 4\).
Compute \$6x\( by multiplying 6 with \)-3 + 4i$.
Add the results from \(x^2\), \$6x$, and the constant term 25 together.
Simplify the expression by combining like terms (real and imaginary parts separately) and verify if the sum equals 0, which confirms that \(-3 + 4i\) is a solution.

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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. Understanding how to work with complex numbers is essential for evaluating expressions involving imaginary parts.
추천 영상:
04:22
Dividing Complex Numbers

Substitution in Polynomial Equations

Substitution involves replacing the variable in an equation with a given value to verify if it satisfies the equation. Here, substituting -3 + 4i into the quadratic equation tests whether it is a root.
추천 영상:
5:48
Solving Systems of Equations - Substitution

Simplifying Expressions with Imaginary Numbers

Simplifying expressions with imaginary numbers requires applying algebraic operations and using i² = -1 to reduce terms. This process helps determine if the substituted value makes the equation true.
추천 영상:
05:07
Simplifying Algebraic Expressions