Algebra 1 : How to find slope of a line

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #31 : How To Find Slope Of A Line

\displaystyle \small (4,2)(14,6)

What is the slope of the line that passes through these two points? 

Possible Answers:

\displaystyle \small \frac{2}{5}

\displaystyle \small \frac{4}{2}

\displaystyle \small 13

\displaystyle \small 4

Correct answer:

\displaystyle \small \frac{2}{5}

Explanation:

The slope is defined as the slant measurement of a line, quantitatively the amount of units that one must "rise", over the amout of units one must "run," or move horizontally across the graph. \displaystyle \small \small (4,2)(14,6) are the points given.

We must find the slope of the line that would pass through both of these points.

To do so, we use the formula: 

\displaystyle \small \frac{y_{1}-y_{2}}{x_{1}-x_{2}}{}.

For these two points, our formula would look like this: 

\displaystyle \small \small \frac{6-2}{14-4} = \frac{4}{10} = \frac{2}{5}.

Thus \displaystyle \small \small \frac{2}{5} is our slope. 

Example Question #192 : Equations Of Lines

Find the slope of \displaystyle 10x+9y=8.

Possible Answers:

\displaystyle 10

\displaystyle -\frac{4}{5}

\displaystyle \frac{10}{9}

\displaystyle 9

\displaystyle -\frac{10}{9}

Correct answer:

\displaystyle -\frac{10}{9}

Explanation:

Rewrite the equation in slope intercept form.

\displaystyle y=mx+b

Where \displaystyle m represents the slope of the line and \displaystyle b represents the \displaystyle y-intercept.

\displaystyle 10x+9y=8

\displaystyle 9y=-10x+8

\displaystyle y=-\frac{10}{9}x+8

The slope is 

\displaystyle -\frac{10}{9}.

Example Question #192 : Equations Of Lines

Given the points \displaystyle (2,3) and \displaystyle (4,6).

Find the slope of the line.

Possible Answers:

\displaystyle 2

\displaystyle \frac{3}{2}

\displaystyle \frac{2}{3}

\displaystyle \frac{1}{2}

\displaystyle 4

Correct answer:

\displaystyle \frac{3}{2}

Explanation:

Use the given points and plug them into slope formula:

\displaystyle m=\frac{\left ( y_{2}-y_{1} \right )}{(x_{2}-x_{1})}

Remember points are written in the following format:

\displaystyle (x,y)

 Substitute.

\displaystyle m=\frac{6-3}{4-2}

Simplify:

\displaystyle m=\frac{3}{2}

 

Example Question #193 : Equations Of Lines

What is the slope of the line between points \displaystyle (0,4) and \displaystyle (2,2)?

Possible Answers:

\displaystyle 4

\displaystyle -1

\displaystyle 1

\displaystyle 2

\displaystyle -2

Correct answer:

\displaystyle -1

Explanation:

The question asks for the slope of the line between two points.

*Always remember what the question is asking.

\displaystyle Slope = m = rise/run = \frac{y_2-y_1}{x_2-x_1}

Using coordinates

\displaystyle (x_1, y_1)=({\color{Magenta} 0},{\color{DarkOrange} 4} ), (x_2,y_2)= ( 2,2),

and plugging them into the slope formula we get the following.

\displaystyle \frac{2-{\color{DarkOrange} 4}}{2-{\color{Magenta} 0}} = \frac{-2}{2}= -1

Example Question #194 : Equations Of Lines

What is the slope of the equation \displaystyle \frac{y-3x}{2}=4?

Possible Answers:

\displaystyle 3

\displaystyle -3/2

\displaystyle 6

\displaystyle 8

\displaystyle -3

Correct answer:

\displaystyle 3

Explanation:

The question is asking for the slope of the equation.

\displaystyle y=mx+b is the general form of an equation

"\displaystyle m" is the slope of the equation, meaning how steep the line of the representing graph would be.

In order to find \displaystyle m, you balance the equation to put it in the general format.

\displaystyle \frac{y-3x}{2}=4

\displaystyle y-3x=8

\displaystyle y={\color{Magenta} 3}x+8

\displaystyle m={\color{Magenta} 3}

 

Example Question #195 : Equations Of Lines

Find the slope of the line crossing through the points \displaystyle \small (2,4) (10,7)

Possible Answers:

\displaystyle \frac{3}{8}

\displaystyle \small \frac{8}{3}

\displaystyle \small -\frac{8}{3}

\displaystyle \small -\frac{3}{8}

Correct answer:

\displaystyle \frac{3}{8}

Explanation:

To find the slope of a line, all we need is the coordinates of two points that lie on the line. We are provided with two points in this problem.

The formula used is: 

\displaystyle \small \small \frac{y_{2}-y_{1}}{x_{2}-x_{1}}.

If we plug in the points provided: 

\displaystyle \small \small \frac{7-4}{10-2}= \frac{3}{8}.

Thus, our slope means that between these two points, we must rise 3 units and run 8 positive units. 

Example Question #31 : How To Find Slope Of A Line

What is the slope of the line that goes through the points \displaystyle (-5, 1)\text{ and }(6, 2)?

Possible Answers:

\displaystyle -\frac{11}{3}

\displaystyle -\frac{5}{3}

\displaystyle 11

\displaystyle \frac{1}{11}

Correct answer:

\displaystyle \frac{1}{11}

Explanation:

The slope of a line is given by the following equation:

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}

For the line in question,

\displaystyle \text{Slope}=\frac{2-1}{6-(-5)}=\frac{1}{11}

Example Question #32 : How To Find Slope Of A Line

Find the slope of the line that goes through the following points: \displaystyle (-1, 1), (6, 0).

Possible Answers:

\displaystyle -\frac{1}{7}

\displaystyle 7

\displaystyle -\frac{1}{5}

\displaystyle \frac{1}{7}

Correct answer:

\displaystyle -\frac{1}{7}

Explanation:

The slope of a line is given by the following equation:

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}

For the line in question,

\displaystyle \text{Slope}=\frac{0-1}{6-(-1)}=-\frac{1}{7}

Example Question #33 : How To Find Slope Of A Line

Find the slope of the line that goes through the following points: \displaystyle (1, 1), (-2, -6)

Possible Answers:

\displaystyle -2

\displaystyle -\frac{7}{3}

\displaystyle \frac{7}{3}

\displaystyle -\frac{4}{7}

Correct answer:

\displaystyle \frac{7}{3}

Explanation:

The slope of a line is given by the following equation:

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}

For the line in question,

\displaystyle \text{Slope}=\frac{-6-1}{-2-1}=\frac{-7}{-3}=\frac{7}{3}

Example Question #34 : How To Find Slope Of A Line

Find the slope of the line that goes through the following points: \displaystyle (10, 5), (-1, 0).

Possible Answers:

\displaystyle \frac{5}{11}

\displaystyle -5

\displaystyle -\frac{1}{2}

\displaystyle \frac{11}{5}

Correct answer:

\displaystyle \frac{5}{11}

Explanation:

The slope of a line is given by the following equation:

\displaystyle \text{Slope}=\frac{y_2-y_1}{x_2-x_1}

For the line in question,

\displaystyle \text{Slope}=\frac{0-5}{-1-10}=\frac{-5}{-11}=\frac{5}{11}

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