Algebra 1 : How to find out if lines are parallel

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #113 : Parallel Lines

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Subtract  from both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify. Remember that when a positive number is divided by a negative number, the answer is always negative.

Subtracting a negative number is the same as adding a positive number. Rewrite.

Reduce.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #71 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Subtract  from both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #71 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Subtract  from both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #121 : Parallel Lines

Which of the following pairs of lines are parallel?

Possible Answers:

Correct answer:

Explanation:

Lines can be written in the slope-intercept form:

In this form,  equals the slope and  represents where the line intersects the y-axis.

Parallel lines have the same slope: .

Only one choice contains tow lines with the same slope.

The slope for both lines in this pair is .

Example Question #73 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Add  to both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #74 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Subtract  from both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify. Remember that when a positive number is divided by a negative number, the answer is always negative.

.

Subtracting a negative number is the same as adding a positive number. Rewrite.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #122 : Parallel Lines

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Subtract  from both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify. Remember that when a positive number is divided by a negative number, the answer is always negative.

Subtracting a negative number is the same as adding a positive number. Rewrite.

Rearrange terms to match the slope-intercept form.

n the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #71 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Add  to both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Reduce.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

Example Question #77 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Add  to both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Rearrange terms to match the slope-intercept form.

In the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

 

Example Question #78 : How To Find Out If Lines Are Parallel

Find 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.

First, put the given line in  form.

We need to isolate  on the left side of the equation. Add  to both sides of the equation.

Simplify.

Divide both sides of the equation by .

Simplify.

Reduce.

Rearrange terms to match the slope-intercept form.

n the given equation:

Parallel lines share the same slope.

Only one of the choices has a slope of .

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