Algebra 1 : Functions and Lines

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #4 : How To Find The Equation Of A Line

Given two points   and , find the equation of a line that passes through the point  and is parallel to the line passing through points  and .

Possible Answers:

Correct answer:

Explanation:

The slope of the line passing through points  and  can be computed as follows:

Now, the new line, since it is parallel, will have the same slope.  To find the equation of this new line, we use point-slope form:

, where  is the slope and  is the point the line passes through.

After rearranging, this becomes

Example Question #1 : How To Find The Equation Of A Line

Find the equation, in  form, of the line that contains the points  and .

Possible Answers:

Correct answer:

Explanation:

When finding the equation of a line from some of its points, it's easiest to first find the line's slope, or .

To find slope, divide the difference in  values by the difference in  values. This gives us  divided by , or .

Next, we just need to find , which is the line's -intercept. By plugging one of the points into the equation , we obtain a  value of 11 and a final equation of

Example Question #2 : How To Find The Equation Of A Line

What is the equation of a straight line that connects the points indicated in the table?

Question_5

Possible Answers:

Correct answer:

Explanation:

We can find the equation of th line in slope-intercept form by finding and .

First, calculate the slope, , for any two points. We will use the first two.

Next, using the slope and any point on the line, calculate the y-intercept, . We will use the first point.

The correct equation in slope-intercept form is .

Example Question #1 : How To Find The Equation Of A Line

What is the equation of a line with a slope of  and a -intercept of ?

Possible Answers:

None of the above

Correct answer:

Explanation:

When a line is in the  format, the  is its slope and the  is its -intercept. In this case, the equation with a slope of  and a -intercept of  is .

Example Question #5 : How To Find The Equation Of A Line

In 1990, the value of a share of stock in General Vortex was $27.17. In 2000, the value was $48.93. If the value of the stock rose at a generally linear rate between those two years, which of the following equations most closely models the price of the stock, , as a function of the year, ?

Possible Answers:

Correct answer:

Explanation:

We can treat the price of the stock as the value and the year as the value, making any points take the form , or . This question is asking for the line that includes points  and 

To find the equation, first, we need the slope.

Now use the point-slope formula with this slope and either point (we will choose the second).

Example Question #6 : How To Find The Equation Of A Line

Possible Answers:

Correct answer:

Explanation:

Example Question #7 : How To Find The Equation Of A Line

Which of these lines has a slope of 5 and a -intercept of 6?

Possible Answers:

 

Correct answer:

Explanation:

When an equation is in the form, the indicates its slope while the indicates its -intercept. In this case, we are looking for a line with a of 5 and a of 6, or .

Example Question #11 : Slope And Line Equations

Which of these lines has a slope of  and a -intercept of ?

Possible Answers:

None of the other answers

Correct answer:

Explanation:

When a line is in the form, the is its slope and the is its -intercept. Thus, the only line with a slope of and a -intercept of is

.

Example Question #12 : Slope And Line Equations

What is the equation of a line with a slope of 3 that runs through the point (4,9)?

Possible Answers:

None of the other answers

Correct answer:

Explanation:

You can find the equation by plugging in all of the information to the formula.

The slope (or ) is 3. So, the equation is now .

You are also given a point on the line: (4,9), which you can plug into the equation:

Solve for to get .

Now that you have the and , you can determine that the equation of the line is .

Example Question #13 : Slope And Line Equations

What is the equation of the line passing through the points (1,2) and (3,1) ?

Possible Answers:

Correct answer:

Explanation:

First find the slope of the 2 points:

Then use the slope and one of the points to find the y-intercept:

So the final equation is 

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