Pre-Algebra : Graphing

Study concepts, example questions & explanations for Pre-Algebra

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Example Questions

Example Question #31 : Graphing

Write the ordered pair of points a, b, and c.

Coordinate plane

Possible Answers:

\displaystyle a= (0, 4),\ b =(0, -5),\ c =(0, -5)

\displaystyle a =(4, 1),\ b =(2, -5),\ c= (-5, 0)

\displaystyle a =(1, 4),\ b= ( -5, 2),\ c =(0, -5)

\displaystyle a= ( 1, 5),\ b= ( 1, 7),\ c =( 1, 5)

\displaystyle a =(1, 4),\ b =(5, 2),\ c =(5, 0)

Correct answer:

\displaystyle a =(1, 4),\ b= ( -5, 2),\ c =(0, -5)

Explanation:

An ordered is always written in the following format:

\displaystyle a= (x, y)

where x is the position on the x-axis, and y is the position on the y-axis.

Coordinate plane

If we look at point a, we find where it falls on the x-axis.  We can see that it's position on the x-axis is 1.  Then, we see where it falls on the y-axis. It's position on the y-axis is 4.  So, we can write the ordered pair for point a as

\displaystyle a =(1, 4)

We will do the same for b.  The position of point b on the x-axis is -5.  The position of point b on the y-axis is 2.  So, we can write the ordered pair for point b as

\displaystyle b= (-5, 2)

And finally for c.  The position of point c on the x-axis is zero.  The position of point c on the y-axis is -5.  So, we can write the ordered pair of point c as

\displaystyle c= (0, -5)

Example Question #31 : Graphing

Which of the following points is found in the second quadrant of a coordinate plane?

Possible Answers:

\displaystyle (3, -4)

\displaystyle (-3, -4)

\displaystyle (3, 4)

\displaystyle (-3, 4)

\displaystyle (0, -4)

Correct answer:

\displaystyle (-3, 4)

Explanation:

The following coordinate plane displays the different quandrants.

 Quadrants

You can also see there is a point that has been graphed.  

That point is (-3, 4).  

Therefore, (-3, 4) can be found in the second quandrant of a coordinate plane.

Example Question #13 : Graphing Points

Find the midpoint of the following points:

(-5, 6) and (1, 2)

Possible Answers:

\displaystyle (-2, 4)

\displaystyle (-5, 12)

\displaystyle (-4, 8)

\displaystyle (-6, 4)

\displaystyle (-3, 4)

Correct answer:

\displaystyle (-2, 4)

Explanation:

The midpoint formula is

\displaystyle (\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2})

where \displaystyle (x_1, y_1) and \displaystyle (x_2, y_2) are the points given.  So, using the points

(-5, 6) and (1, 2) we can substitute into the midpoint formula and get

\displaystyle (\frac{-5 + 1}{2}, \frac{6 + 2}{2})

\displaystyle (\frac{-4}{2}, \frac{8}{2})

\displaystyle (-2, 4)

Therefore, the midpoint is (-2, 4).

Example Question #14 : Graphing Points

Which quadrant does the coordinates \displaystyle (7, -5) belong to?

 

Possible Answers:

\displaystyle 2

\displaystyle 1

\displaystyle 4

\displaystyle 5

\displaystyle 3

Correct answer:

\displaystyle 4

Explanation:

When looking at a coordinate plane, draw the letter C in there making sure you connect all four quarters of the grid. The C should start in the top right corner, move to the top left, then bottom left, then finish in the bottom right corner.

The quadrants start with \displaystyle 1 and finish with \displaystyle 4.

Therefore the coordinates \displaystyle (7, -5) means \displaystyle 7 to the right and \displaystyle 5 down which would place the coordinates in quadrant 4.

Example Question #2 : How To Identify A Point In Pre Algebra

What is the slope of the line with the equation \displaystyle y=13x+17?

Possible Answers:

\displaystyle m=4

\displaystyle m=-4

\displaystyle m=17

\displaystyle m=13

Correct answer:

\displaystyle m=13

Explanation:

In the standard form equation of a line, , the slope is represented by the variable .

In this case the line \displaystyle y=13x+17 has a slope of \displaystyle 13.

Therefore the answer is \displaystyle m=13.

Example Question #1 : Graphing Lines

What is the slope of the line that contains the points

\displaystyle (8,12) and \displaystyle (9,-7)?

Possible Answers:

\displaystyle m=-19

\displaystyle m=\frac{1}{2}

\displaystyle m=-13

\displaystyle m=-13

\displaystyle m=8

Correct answer:

\displaystyle m=-19

Explanation:

To find the slope of a line with two points you must properly plug the points into the slope equation for two points which is

\displaystyle m=\frac{Y-y}{X-x}

We must then properly assign the points to the equation as \displaystyle (X,Y) and \displaystyle (x,y).

In this case we will make \displaystyle (9,-7) our  and \displaystyle (8,12) our .

Plugging the points into the equation yields 

\displaystyle m=\frac{-7-12}{9-8}

Perform the math to arrive at 

\displaystyle m=\frac{-19}{1}

The answer is \displaystyle m=-19.

Example Question #32 : Graphing

What is the slope of the line \displaystyle y=15x+13?

Possible Answers:

\displaystyle 13

\displaystyle 5

\displaystyle x

\displaystyle 15

Correct answer:

\displaystyle 15

Explanation:

In the standard form of a line \displaystyle y=mx+b the slope is represented by the variable \displaystyle m.

In this case the line \displaystyle y=15x+13 has a slope of \displaystyle 15.

The answer is \displaystyle 15.

Example Question #32 : Graphing

The equation of a line is \displaystyle y=4x-7.

What are the slope and the y-intercept?

Possible Answers:

Slope: \displaystyle \frac{1}{4}

y-intercept: \displaystyle (0,7)

Slope: \displaystyle 4

y-intercept: \displaystyle (0,7)

Slope: \displaystyle \frac{1}{4}

y-intercept: \displaystyle (0,-7)

Slope: \displaystyle 4

y-intercept: \displaystyle (0,-7)

Correct answer:

Slope: \displaystyle 4

y-intercept: \displaystyle (0,-7)

Explanation:

The equation of the line is written in slope-intercept form, \displaystyle y=mx+b, where \displaystyle m is the slope and \displaystyle b is the y-intercept. In this example, the y-intercept is a negative number.

\displaystyle y=4x-7

\displaystyle m=4

\displaystyle b=-7

Example Question #33 : Graphing

What is the y-intercept of the line \displaystyle y=16x+91?

Possible Answers:

\displaystyle (16,91)

\displaystyle (91,0)

\displaystyle (91,16)

\displaystyle (0,91)

Correct answer:

\displaystyle (0,91)

Explanation:

The y-intercept is the point at which the line intersects the y-axis.

It does this at .

We plug  in for  in our equation, \displaystyle y=16x+91, to give us \displaystyle y=16(0)+91.

Anything multiplied by  is , so \displaystyle y=91.

Our coordinates for the y-intercept are \displaystyle (0,91).

Example Question #2 : How To Identify A Point In Pre Algebra

What is the slope of the line \displaystyle y=15x+92?

Possible Answers:

\displaystyle m=15

\displaystyle m=92

\displaystyle m=35

\displaystyle m=5

Correct answer:

\displaystyle m=15

Explanation:

In the slope-intercept form of a line, , the slope is represented by the variable .

In this case the line

 

has a slope of .

The answer is \displaystyle m=15.

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