Algebra 1 : How to find the slope of parallel lines

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #1 : How To Find The Slope Of Parallel Lines

What is the slope of a line parallel to the line described by 3x + 8y =16?

Possible Answers:

Correct answer:

Explanation:

First, you should put the equation in slope intercept form (y = mx + b), where m is the slope.   

Isolate the y term

3x + 8y – 3x = 16 – 3x

8y = 16 – 3x

Rearrange terms

8y = –3x +16

Divide both sides by 8

The slope of the line is -3/8. A parallel line will have the same slope, thus -3/8 is the correct answer.

Example Question #2 : How To Find The Slope Of Parallel Lines

What is the slope of a line parallel to  ?

Possible Answers:

Correct answer:

Explanation:

When two lines are parallel, they have the same slope. With this in mind we take the slope of the first line which is   and make it the slope of our parallel line.

If , then .

Example Question #1 : How To Find The Slope Of Parallel Lines

What is the slope of a line that is parallel to ?

Possible Answers:

Correct answer:

Explanation:

Parallel lines have identical slopes. To determine the slope of the given line, transform into the format, or . The slope of the given line is , so its parallel line must also be .

Example Question #3 : How To Find The Slope Of Parallel Lines

Which equation described a line parallel to the line that connects points (–8,9) and (3,–4)?

Possible Answers:

Correct answer:

Explanation:

In order for two lines to be parellel, their slopes have to be the same.

Find the slope of the line connecting those two points using the general slope formula, , where the points are  and .  In our case, the points are (–8,9) and (3,–4).  The slope is calculated below.

Match this slope value with one of the possible choice of equations. The correct equation is because its slope is the same.

Example Question #1 : How To Find The Slope Of Parallel Lines

Which of the following are NOT parallel to each other?

Possible Answers:

Correct answer:

Explanation:

Four of the answers are not in slope-intercept form.

 For the lines to be parallel, all must share the same slopes.  

To identify the slopes, this is the  term of:

The only equation that does not have a slope of  is

.

Example Question #6 : How To Find The Slope Of Parallel Lines

Lines A and B are parallel. Line A can be represented by the equation .

Find the slope of line B.

Possible Answers:

Correct answer:

Explanation:

If two lines are parallel, then they have the same slope.

Line A is:

Rewrite this in slope-intercept form where  is the slope:

The slope of line A is .

If the slope of line A is , then the slope of line B must be

Example Question #7 : How To Find The Slope Of Parallel Lines

Find the slope of a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

Lines can be written in the slope-intercept format:

In this format,  equals the line's slope and  represents where the line intercepts the y-axis.

In the given equation:

And it has a slope of:

Parallel lines share the same slope.

The parallel line has a slope of .

Example Question #3 : How To Find The Slope Of Parallel Lines

Find the slope of a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

Lines can be written in the slope-intercept format:

In this format,  equals the line's slope and  represents where the line intercepts the y-axis.

In the given equation:

And it has a slope of:

Parallel lines share the same slope.

The parallel line has a slope of .

Example Question #4 : How To Find The Slope Of Parallel Lines

Find the slope of a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

Lines can be written in the slope-intercept format:

In this format,  equals the line's slope and  represents where the line intercepts the y-axis.

In the given equation:

And it has a slope of:

Parallel lines share the same slope.

The parallel line has a slope of .

Example Question #1 : How To Find The Slope Of Parallel Lines

Find the slope of a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

Lines can be written in the slope-intercept format:

In this format,  equals the line's slope and  represents where the line intercepts the y-axis.

In the given equation:

And it has a slope of:

Parallel lines share the same slope.

The parallel line has a slope of .

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