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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 3, Problem 16a

Use the given conditions to write an equation for each line in point-slope form and slope-intercept form. Slope = -5, passing through (-4, -2)

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Start with the point-slope form of a linear equation: y - y_1 = m(x - x_1), where m is the slope and (x_1, y_1) is a point on the line.
Substitute the given slope m = -5 and the point (x_1, y_1) = (-4, -2) into the point-slope form. This gives: y - (-2) = -5(x - (-4)).
Simplify the equation by removing the double negatives: y + 2 = -5(x + 4). This is the equation in point-slope form.
To convert to slope-intercept form, expand the equation: Distribute -5 to both terms inside the parentheses: y + 2 = -5x - 20.
Isolate y by subtracting 2 from both sides: y = -5x - 22. This is the equation in slope-intercept form.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Point-Slope Form

Point-slope form is a way to express the equation of a line when you know the slope and a point on the line. It is written as y - y1 = m(x - x1), where (x1, y1) is the point and m is the slope. This form is particularly useful for quickly writing the equation of a line when given a slope and a specific point.
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Slope-Intercept Form

Slope-intercept form is another way to express the equation of a line, defined as y = mx + b, where m is the slope and b is the y-intercept. This form is beneficial for easily identifying the slope and where the line crosses the y-axis. Converting from point-slope to slope-intercept form involves rearranging the equation to isolate y.
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Slope-Intercept Form

Slope

The slope of a line measures its steepness and direction, calculated as the change in y divided by the change in x (rise over run). A negative slope indicates that the line descends from left to right, while a positive slope indicates it ascends. Understanding slope is crucial for graphing lines and interpreting their behavior in relation to other lines.
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