Algebra 1 : Functions and Lines

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #62 : How To Find The Equation Of A Line

Given the slope of a line is five, and a point on the graph is , write the equation of the line in point-slope form.

Possible Answers:

Correct answer:

Explanation:

Write the formula for point-slope form.

The variable  is the slope, and the point is in  format.  

Substitute all the givens.   There's is no need to simplify.

The answer is:  

Example Question #155 : Equations Of Lines

Given the slope is three, and a point is  on the graph, what is the equation of the line?

Possible Answers:

Correct answer:

Explanation:

Write the slope intercept form.

Substitute the slope and the point to find the y-intercept, .

Solve for the unknown variable.

Subtract nine from both sides.

Write the equation now that we have the slope and y-intercept.

The answer is: 

Example Question #156 : Equations Of Lines

Find the equation of the line given two points:   and 

Possible Answers:

Correct answer:

Explanation:

Write the slope intercept form.  The equation will be in this form.

Write the slope formula.

Let  and .  

Substitute the points into the slope formula.

The slope is:  

Use the slope and a given point, substitute them into the slope intercept form to find the y-intercept.

Solve for the y-intercept.

Add two-thirds on both sides.

Simplify both sides.

With the slope and y-intercept known, write the formula.

The answer is:  

Example Question #157 : Equations Of Lines

Given the x-intercept is seven, and the y-intercept is four, what is the equation of the line?

Possible Answers:

Correct answer:

Explanation:

The x-intercept is the value when .

The y-intercept is the value when .

We know the two points needed to find the equation of the line.

The points are:   and 

Use the slope formula to find the slope.

Write the slope-intercept equation.

Substitute the slope and the y-intercept.

The answer is:  

Example Question #158 : Equations Of Lines

If the slope is four, and a known point is , what is the equation in point-slope form?

Possible Answers:

Correct answer:

Explanation:

Write the equation in point-slope form.

The variable  is the slope.  Substitute the slope and the point.

Simplify the right side of the equation.

The answer is:  

Example Question #161 : Equations Of Lines

A line passes through the points (3, 9) and (5, 3), and has a y-intercept of 3.  Which of the following is an equation for that line?

Possible Answers:

 

Correct answer:

 

Explanation:

The equation for a line is always , where  and .

Given two data points, we are able to find the slope, m, using the formula 

.

Using the data points provided, our formula will be: 

, which gives us  or , .

Our y-intercept is given.

Thus our equation for the line containing these points and that y-intercept is .

Example Question #1 : How To Find Slope Of A Line

What is the slope of the equation 4x + 3y = 7?

Possible Answers:

–3/4

4/3

–7/3

–4/3

3/4

Correct answer:

–4/3

Explanation:

We should put this equation in the form of y = mx + b, where m is the slope.

We start with 4x + 3y = 7.

Isolate the y term: 3y = 7 – 4x

Divide by 3: y = 7/3 – 4/3 * x

Rearrange terms: y = –4/3 * x + 7/3, so the slope is –4/3.

Example Question #1 : How To Find Slope Of A Line

Find the slope of the line through the points (6,2) and (3,4).

Possible Answers:

Correct answer:

Explanation:

The equation for slope is . You plug in the coordinates from the points given you, and get , giving you . Note that it does not matter which point you use as point 1 and point 2, as long as you are consistent.

(6,2) = (x1,y1)

(3,4) = (x2,y2)

Example Question #1 : How To Find Slope Of A Line

Given the line 4y = 2x + 1, what is the slope of this line?

Possible Answers:

–2

2

–1/4

1/2

1/4

Correct answer:

1/2

Explanation:

4y = 2x + 1 becomes y = 0.5x + 0.25. We can read the coefficient of x, which is the slope of the line.

4y = 2x + 1

(4y)/4 = (2x)/4 + (1)/4

y = 0.5x + 0.25

y = mx + b, where the slope is equal to m.

The coefficient is 0.5, so the slope is 1/2.

Example Question #2 : How To Find Slope Of A Line

What is the slope of the line containing the points (7,12) and (91,32).

Possible Answers:

Correct answer:

Explanation:

To find the slope of a line you must first assign variables to each point. It does not matter which points get which variables as long as you keep the  and  and  and  consistent when you plug them into the equation.

Then we plug in the variables to this equation where  represents the slope.

Then we plug in our points for and the example looks like

Then we perform the necessary subtraction and division to find an answer of 

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