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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 23a

Write an equation in slope-intercept form of a linear function f whose graph satisfies the given conditions. The graph of ƒ is perpendicular to the line whose equation is 3x - 2y - 4 = 0 and has the same y-intercept as this line.

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1
Rewrite the given equation 3x - 2y - 4 = 0 in slope-intercept form (y = mx + b) by isolating y. Start by moving the terms involving x and the constant to the other side: -2y = -3x + 4.
Divide through by -2 to solve for y: y = (3/2)x - 2. This gives the slope (m) of the given line as 3/2 and the y-intercept (b) as -2.
Recall that perpendicular lines have slopes that are negative reciprocals of each other. The slope of the new line will be the negative reciprocal of 3/2, which is -2/3.
Since the new line has the same y-intercept as the given line, the y-intercept (b) remains -2.
Write the equation of the new line in slope-intercept form using the slope (-2/3) and y-intercept (-2): y = (-2/3)x - 2.

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Key Concepts

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

Slope-Intercept Form

The slope-intercept form of a linear equation is expressed as y = mx + b, where m represents the slope and b represents the y-intercept. This form is useful for quickly identifying the slope of the line and where it crosses the y-axis, making it easier to graph linear functions.
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Perpendicular Lines

Two lines are perpendicular if the product of their slopes is -1. This means that if one line has a slope of m, the other line will have a slope of -1/m. Understanding this relationship is crucial for finding the slope of a line that is perpendicular to a given line.
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Finding the Y-Intercept

The y-intercept of a line is the point where the line crosses the y-axis, which occurs when x = 0. To find the y-intercept from a linear equation, you can rearrange the equation into slope-intercept form or directly substitute x = 0 into the equation. This value is essential for constructing the equation of a line with a specific y-intercept.
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