Skip to main content
Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 11

Use the given conditions to write an equation for each line in point-slope form and general form. Passing through (4, −7) and perpendicular to the line whose equation is x − 2y – 3 = 0

검증된 단계별 안내
1
Identify the slope of the given line by rewriting its equation \(x - 2y - 3 = 0\) in slope-intercept form \(y = mx + b\). Start by isolating \(y\): add \$2y\( to both sides and subtract \(3\) from both sides to get \)x - 3 = 2y\(, then divide both sides by 2 to find \(y = \frac{1}{2}x - \frac{3}{2}\), so the slope \)m$ of the given line is \(\frac{1}{2}\).
Determine the slope of the line perpendicular to the given line. Recall that perpendicular slopes are negative reciprocals, so if the original slope is \(\frac{1}{2}\), the perpendicular slope will be \(-2\).
Use the point-slope form of a line equation, which is \(y - y_1 = m(x - x_1)\), where \((x_1, y_1)\) is the point the line passes through and \(m\) is the slope. Substitute the point \((4, -7)\) and the perpendicular slope \(-2\) into the formula to get \(y - (-7) = -2(x - 4)\).
Simplify the point-slope form equation to make it clearer: \(y + 7 = -2(x - 4)\).
Convert the point-slope form to the general form \(Ax + By + C = 0\) by distributing and rearranging terms. Start by expanding the right side: \(y + 7 = -2x + 8\), then bring all terms to one side to get \(2x + y - 1 = 0\).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
3m
도움이 되었나요?

주요 개념

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

Point-Slope Form of a Line

The point-slope form expresses a line's equation using a known point (x₁, y₁) and the slope m, written as y - y₁ = m(x - x₁). It is useful for writing equations when a point and slope are given, allowing easy substitution to find the line's equation.
추천 영상:
가이드 코스
05:46
Point-Slope Form

Slope of a Line from General Form

A line in general form Ax + By + C = 0 can be rewritten to slope-intercept form y = mx + b, where the slope m = -A/B. Finding the slope from the general form is essential to determine relationships like parallelism or perpendicularity between lines.
추천 영상:
가이드 코스
02:35
Graphing Lines in Slope-Intercept Form

Perpendicular Lines and Their Slopes

Two lines are perpendicular if their slopes are negative reciprocals, meaning m₁ * m₂ = -1. Knowing this relationship helps find the slope of a line perpendicular to a given line, which is crucial for writing the equation of the required line.
추천 영상:
가이드 코스
07:52
Parallel & Perpendicular Lines