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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 14a

Use the given conditions to write an equation for each line in point-slope form and slope-intercept form. Slope = 8, passing through (4, −1)

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Step 1: Recall the point-slope form of a linear equation, which is given by: y - y_1 = m(x - x_1), where m is the slope and (x_1, y_1) is a point on the line.
Step 2: Substitute the given slope m = 8 and the point (x_1, y_1) = (4, -1) into the point-slope form. This gives: y - (-1) = 8(x - 4).
Step 3: Simplify the equation from Step 2. The double negative becomes positive, so the equation becomes: y + 1 = 8(x - 4). This is the equation in point-slope form.
Step 4: To convert to slope-intercept form, expand the equation y + 1 = 8(x - 4). Distribute the 8 to get: y + 1 = 8x - 32.
Step 5: Isolate y by subtracting 1 from both sides of the equation. This gives: y = 8x - 33. 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

The point-slope form of a linear equation is expressed as y - y₁ = m(x - x₁), where (x₁, y₁) is a point on the line and m is the slope. This form is particularly useful for writing equations when you know a point on the line and the slope, allowing for straightforward calculations and graphing.
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Slope-Intercept Form

The slope-intercept form of a linear equation is given by y = mx + b, where m represents the slope and b is the y-intercept. This form is advantageous for quickly identifying the slope and the point where the line crosses the y-axis, making it easier to graph the line and understand its behavior.
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Slope-Intercept Form

Slope

Slope is a measure of the steepness or incline of a line, calculated as the ratio of the vertical change (rise) to the horizontal change (run) between two points on the line. In this case, a slope of 8 indicates that for every unit increase in x, y increases by 8 units, which significantly influences the line's angle and position.
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