GED Math : Points and Lines

Study concepts, example questions & explanations for GED Math

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Example Questions

Example Question #1 : Points And Lines

What is the -intercept of the line of the equation  ?

Possible Answers:

The line has no -intercept. 

Correct answer:

Explanation:

The -intercept, the point at which a line intersects the -axis, has -coordinate 0, so substitute 0 for  and solve for  to find the -coordinate:

The -intercept is the point 

Example Question #2 : Points And Lines

What is the -coordinate of the point at which the lines of these two equations intersect?

Possible Answers:

Correct answer:

Explanation:

The elimination method will work here. Multiply the second equation by  on both sides, then add to the first:

   

 

Example Question #3 : Points And Lines

What is the -coordinate of the point at which the lines of these two equations intersect?

Possible Answers:

The lines of the equations do not intersect.

Correct answer:

Explanation:

The elimination method will work here. Multiply the second equation by  on both sides, then add to the first:

   

         

Example Question #4 : Points And Lines

What is the -coordinate of the point at which the lines of these two equations intersect?

Possible Answers:

The lines do not intersect at any point.

Correct answer:

Explanation:

The elimination method will work here. Multiply the second equation by  on both sides, then add to the first:

    

                 

Example Question #5 : Points And Lines

What is the -coordinate of the point at which the lines of these two equations intersect?

Possible Answers:

Correct answer:

Explanation:

The elimination method will work here. Multiply the second equation by 3 on both sides, then add to the first:

Example Question #5 : Points And Lines

Which of the following is an equation for the line between the points  and ?

Possible Answers:

Correct answer:

Explanation:

Probably the easiest way to solve this question is to use the point-slope form of an equation.  Remember that for that format, you need a point and the slope of the line.  (Pretty obvious, given the name!)  For a point , the point-slope form is:

, where  is the slope

Now, recall that the slope is calculated from two points using the formula:

For our data, this is:

Thus, for your point-slope form of the line, you get the equation:

Just simplify things now...

Example Question #6 : Points And Lines

Which of the following is an equation for the line between the points  and ?

Possible Answers:

Correct answer:

Explanation:

Probably the easiest way to solve this question is to use the point-slope form of an equation.  Remember that for that format, you need a point and the slope of the line.  (Pretty obvious, given the name!)  For a point , the point-slope form is:

, where  is the slope

Now, recall that the slope is calculated from two points using the formula:

For our data, this is:

Now, that is an awkward slope, but just be careful with the simplification.  For the point-slope form of the line, you get the equation:

Just simplify things now...

Now, find a common denominator for the fractions.  (It is .)

 

Example Question #5 : Points And Lines

Which of the following lines contains the point ?

Possible Answers:

Correct answer:

Explanation:

To solve for a question like this, the easiest thing to do is to plug in your  and  values to see what happens.  If you get two numbers equal to each other when they are, in fact, unequal, you do not have a working case.  

For example, consider the wrong option, 

Substitute in your values, and you get:

 or 

Now, for your correct option, you get:

This certainly makes sense!  It also means that the point is on the line in question!

Example Question #5 : Points And Lines

Which of the following points is on the line ?

Possible Answers:

Correct answer:

Explanation:

Upon substitution of the answer choices, we will need to satisfy the equation, by plugging in the x and y-values of the points given.

The answer is:  

Example Question #9 : Points And Lines

Find the equation of the line given the two points  and .

Possible Answers:

Correct answer:

Explanation:

The equation of a line in slope-intercept form is .

Write the formula for slope.

Substitute the points.

The y-intercept from the point  means that .

The equation of the line is:  

The answer is:  

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