ElementaryAlgebra2e-WEB_3zxfu3Z-96

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Use to find the Slope of a Line from its Graph
In the following exercises, find the slope of each line shown.
227. 228.
229. 230.
231. 232.
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233. 234.
235. 236.
237. 238.
4.4 • Understand Slope of a Line 467
239. 240.
241. 242.
Find the Slope of Horizontal and Vertical Lines
In the following exercises, find the slope of each line.
243. 244. 245.
246. 247. 248.
249. 250.
Use the Slope Formula to find the Slope of a Line between Two Points
In the following exercises, use the slope formula to find the slope of the line between each pair of points.
251. 252. 253.
254. 255. 256.
257. 258. 259.
260. 261. 262.
Graph a Line Given a Point and the Slope
In the following exercises, graph each line with the given point and slope.
263. ; 264. ; 265. ;
266. ; 267. ; 268. ;
269. ; 270. ; 271. y-intercept 3;
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272. y-intercept 5; 273. x-intercept ; 274. x-intercept ;
275. ; 276. ; 277. ;
278. ;
Everyday Math
ⓐ What is the slope of the roof in this picture?
ⓑ What is the pitch in construction terms?
279. Slope of a roof. An easy way to determine the
slope of a roof is to set one end of a 12 inch level
on the roof surface and hold it level. Then take a
tape measure or ruler and measure from the
other end of the level down to the roof surface.
This will give you the slope of the roof. Builders,
sometimes, refer to this as pitch and state it as
an “ 12 pitch” meaning , where is the
measurement from the roof to the level—the
rise. It is also sometimes stated as an “ -in-12
pitch”.
280. The slope of the roof shown here is measured
with a 12” level and a ruler. What is the slope of
this roof?
281. Road grade. A local road has a grade of 6%. The
grade of a road is its slope expressed as a
percent. Find the slope of the road as a fraction
and then simplify. What rise and run would
reflect this slope or grade?
ⓐ What is the slope of the highway?
ⓑ The grade of a highway is its slope expressed
as a percent. What is the grade of this highway?
282. Highway grade. A local road rises 2 feet for
every 50 feet of highway.
ⓐ How long must the ramp be to
accommodate a 24-inch rise to the door?
ⓑ Create a model of this ramp.
283. Wheelchair ramp. The rules for wheelchair
ramps require a maximum 1-inch rise for a
12-inch run.
ⓐ How long must a ramp be to easily
accommodate a 24-inch rise to the door?
ⓑ Create a model of this ramp.
284. Wheelchair ramp. A 1-inch rise for a 16-inch run
makes it easier for the wheelchair rider to
ascend a ramp.
Writing Exercises
285. What does the sign of the slope tell you about a
line?
286. How does the graph of a line with slope
differ from the graph of a line with slope ?
287. Why is the slope of a vertical line “undefined”?
4.4 • Understand Slope of a Line 469
Self Check
ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.
ⓑ On a scale of 1–10, how would you rate your mastery of this section in light of your responses on the checklist? How
can you improve this?
4.5 Use the Slope-Intercept Form of an Equation of a Line
Learning Objectives
By the end of this section, you will be able to:
Recognize the relation between the graph and the slope–intercept form of an equation of a line
Identify the slope and y-intercept form of an equation of a line
Graph a line using its slope and intercept
Choose the most convenient method to graph a line
Graph and interpret applications of slope–intercept
Use slopes to identify parallel lines
Use slopes to identify perpendicular lines
BE PREPARED 4.10 Before you get started, take this readiness quiz.
Add:
If you missed this problem, review Example 1.77.
BE PREPARED 4.11 Find the reciprocal of
If you missed this problem, review Example 1.70.
BE PREPARED 4.12 Solve .
If you missed this problem, review Example 2.63.
Recognize the Relation Between the Graph and the Slope–Intercept Form of an
Equation of a Line
We have graphed linear equations by plotting points, using intercepts, recognizing horizontal and vertical lines, and
using the point–slope method. Once we see how an equation in slope–intercept form and its graph are related, we’ll
have one more method we can use to graph lines.
In Graph Linear Equations in Two Variables, we graphed the line of the equation by plotting points. See
Figure 4.24. Let’s find the slope of this line.
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	Chapter 4 Graphs
	4.5 Use the Slope-Intercept Form of an Equation of a Line