Algebra 1 : Functions and Lines

Study concepts, example questions & explanations for Algebra 1

varsity tutors app store varsity tutors android store

Example Questions

Example Question #14 : Slope And Line Equations

What is the slope and y-intercept of ?

Possible Answers:

None of the other answers

Slope: ; y-intercept:

Slope: ; y-intercept:

Slope: ; y-intercept:

Slope: ; y-intercept:

Correct answer:

Slope: ; y-intercept:

Explanation:

The easiest way to determine the slope and y-intercept of a line is by rearranging its equation to the form. In this form, the slope is the  and the y-intercept is the .

Rearranging

gives you

which has an of 2 and a of 6.

Example Question #15 : Slope And Line Equations

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

Possible Answers:

Correct answer:

Explanation:

When finding the equation of a line given two or more points, the first step is to find the slope of that line. We can use the slope equation, . Any combination of the three points can be used, but let's consider the first two points,  and .

 

So  is our slope.

Now, we have the half-finished equation

 

and we can complete it by plugging in the  and  values of any point. Let's use .

Solving

  

for  gives us

 

so

 

We now have our completed equation: 

Example Question #16 : Slope And Line Equations

We have two points:  and .

If these two points are connected by a straight line, find the equation describing this straight line.

Possible Answers:

None of these

Correct answer:

Explanation:

We need to find the equation of the line in slope-intercept form.

In this formula, is equal to the slope and is equal to the y-intercept.

To find this equation, first, we need to find the slope by using the formula for the slope between two point.

In the formula, the points are  and .  In our case, the points are  and . Using our values allows us to solve for the slope.

We can replace the variable with our new slope.

Next, we need to find the y-intercept. To find this intercept, we can pick one of our given points and use it in the formula.

Solve for .

Now, the final equation connecting the two points can be written using the new value for the y-intercept.

Example Question #17 : Slope And Line Equations

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

Possible Answers:

None of the other answers

Correct answer:

Explanation:

Since all of the answers are in the  form, the slope of each line is indicated by its  and its y-intercept is indicated by its . Thus, a line with a slope of  and a y-intercept of  must have an equation of .

Example Question #18 : Slope And Line Equations

Find the domain of:

 

Possible Answers:

Correct answer:

Explanation:

The expression under the radical must be .  Hence

 

Solving for , we get

Example Question #19 : Slope And Line Equations

Give, in slope-intercept form, the equation of a line through the points  and .

Possible Answers:

Correct answer:

Explanation:

First, use the slope formula to find the slope, setting .

We can write the equation in slope-intercept form as

.

Replace :

We can find  by substituting for  using either point - we will choose :

The equation is .

Example Question #20 : Slope And Line Equations

Give, in slope-intercept form, the equation of a line through the points  and .

Possible Answers:

Correct answer:

Explanation:

First, use the slope formula to find the slope, setting .

We can write the equation in slope-intercept form as

.

Replace :

We can find  by substituting for  using either point - we will choose :

The equation is .

Example Question #21 : How To Find The Equation Of A Line

Find the equation of the line that is parallel to  and contains the point (0,1).

Possible Answers:

Correct answer:

Explanation:

To find the equation of a line, we need to know the slope and a point that passes through the line.  We can then use the equation  where m is the slope of the line, and  a point on the line.  For parallel lines, the slopes are the same.  The slope of  is 3, so the slope of the parallel line will be 3 as well.  We know that the parallel line needs to contain the point (0,1), so we have all of the information we need.  We can now use the equation 

Example Question #22 : How To Find The Equation Of A Line

Write an equation in the form  for the line that fits the following points:

(4,3), (6,6), (10,12)

Possible Answers:

Correct answer:

Explanation:

The equation of a line is written in the following format: 

1) The first step, then, is to find the slope, .

 is equal to the change in  divided by the change in .

So,

2) Next step is to find . We can find values for  and  from any one of the given points, plug them in, and solve for .

Let's use (4,3)

So, 

Then we just fill in our value for , and we have  as a function of .

Example Question #23 : How To Find The Equation Of A Line

Which of these lines has a slope of 4 and a y-intercept of 6?

Possible Answers:

None of the other answers

Correct answer:

Explanation:

When an equation is in the  form, its slope is  and its y-intercept is . Thus, we need an equation with an  of 4 and a  of 6, which would be 

Learning Tools by Varsity Tutors