Pre-Algebra : Graphing Lines

Study concepts, example questions & explanations for Pre-Algebra

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Example Questions

Example Question #41 : Graphing

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

Possible Answers:

Correct answer:

Explanation:

The slope of a perpendicular lines has the negative reciprocal of the slope of the original line.

If an equation is in slope-intercept form, , we use the  from our equation as our original slope.

In this case 

First flip the sign 

To find the reciprocal you take the integer and make it a fraction by placing a  over it. If it is already a fraction just flip the numerator and denominator.

Do this to make the slope 

The slope of the perpendicular line is

.

Example Question #42 : Graphing

What is the slope of the following line:

Possible Answers:

Correct answer:

Explanation:

To be able to identify the slope of a line, we need to get it in the form of 

.

To do this we need to change the coefficient of y to be  instead of . To do this, divide both sides of the equation by .

Now we can tell what the value of m, or the slope, is: 

Example Question #43 : Graphing

 and  are two points on a line. What is the slope of this line?

Possible Answers:

Correct answer:

Explanation:

The slope of the line is determined by . In other words, we can use the formula .

Let's choose the coordinate  to be ( , )  and  to be ( , ).

We can now use the formula above:

 

Example Question #44 : Graphing

What is the slope of a line containing the points  and ?

Possible Answers:

Correct answer:

Explanation:

The formula to calculate slope  between two points in a line is , for points  and 

If we pick  as our  and  as our , then:


This simplifies to , which can be reduced to  

Example Question #45 : Graphing

What is the slope-intercept form of a line?

Possible Answers:

Correct answer:

Explanation:

 

The slope-intercept form of a line is .

Example Question #46 : Graphing

Which of the follow lines is parallel to:

Possible Answers:

Cannot be determined

Correct answer:

Explanation:

It is known that parallel lines have the same slope and therefore a line that is parallel to:

MUST have the same slope of .

Example Question #51 : Graphing

 

 

Write an equation in point-slope form for a line parallel to the line  

that goes through the point:  .

Possible Answers:

Correct answer:

Explanation:

You know that point-slope form is:  

and therefore you must look at the slope of your equation given which is .

From there you just plug in what is given: 

 for ,

 for ,

and  for 

Example Question #1 : Graphing

A line graphed on the coordinate plane below. Graph_of_y_-2x_4

Give the equation of the line in slope intercept form. 

Possible Answers:

\dpi{100} \small y=-2x+4

\dpi{100} \small y=-x+4

\dpi{100} \small y=-2x-4

\dpi{100} \small y=2x-4

\dpi{100} \small y=2x+4

Correct answer:

\dpi{100} \small y=-2x+4

Explanation:

The slope of the line is \dpi{100} \small -2 and the y-intercept is \dpi{100} \small 4.

The equation of the line is \dpi{100} \small y=-2x+4

Example Question #52 : Graphing

What is the slope and y-intercept of the equation 

Possible Answers:

Correct answer:

Explanation:

The slope intercept formula is:

Example Question #53 : Graphing

What is the slope and y-intercept of the equation below?

Possible Answers:

Slope = 

Y-intercept = 

Slope = 

Y-intercept = 

Slope = 

Y-intercept = 

Slope = 

Y-intercept = 

Slope = 

Y-intercept = 

Correct answer:

Slope = 

Y-intercept = 

Explanation:

In order to understand this question you must understand what slope intercept form is.

 = slope 

 = y-intercept

The slope is 

The y-intercept is 

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