High School Math : How to identify a point in pre-algebra

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : How To Identify A Point In Pre Algebra

What is the slope of the line \displaystyle y=5x-32.

Possible Answers:

\displaystyle 10

\displaystyle -27

\displaystyle 5

\displaystyle 32

Correct answer:

\displaystyle 5

Explanation:

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

In this case the line \displaystyle y=5x-32 has a slope of \displaystyle 5.

The answer is \displaystyle 5.

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

If the equation of a line is \displaystyle y=4x+15, what is the y-intercept?

Possible Answers:

\displaystyle (15,0)

\displaystyle (4,15)

\displaystyle (0,4)

\displaystyle (0,15)

Correct answer:

\displaystyle (0,15)

Explanation:

In the slope-intercept form of a line, , the y-intercept when the line intersects the y-axis.

It does this at \displaystyle x=0.

So we plug \displaystyle 0 in for \displaystyle x in our equation \displaystyle y=4x+15 to give us \displaystyle y=4(0)+15.

Anything multiplied by \displaystyle 0 is \displaystyle 0 so \displaystyle y=15.

Our coordinates for the y-intercept are \displaystyle (0,15).

Example Question #3 : How To Identify A Point In Pre Algebra

What is the y-intercept of the line \displaystyle y=9x-17?

Possible Answers:

\displaystyle (-17,0)

\displaystyle (0,-17)

\displaystyle (9,0)

\displaystyle (0,9)

Correct answer:

\displaystyle (0,-17)

Explanation:

In the standard form of a line  the y-intercept occurs when the line intersects the y-axis.

It does this at 

So we plug  in for  in our equation \displaystyle y=9x-17 to give us \displaystyle y=9(0)-17.

Anything multiplied by  is  so \displaystyle -17.

Our coordinates for the y-intercept are \displaystyle (0,-17).

Example Question #4 : How To Identify A Point In Pre Algebra

What is the slope of a line that is parallel to \displaystyle y=5x+64?

Possible Answers:

\displaystyle 5

\displaystyle -5

\displaystyle -\frac{1}{5}

\displaystyle \frac{1}{5}

Correct answer:

\displaystyle 5

Explanation:

Parallel lines have the same slope.

If an equation is in point-slope form, \displaystyle y=mx+b, we take the \displaystyle m from our equation and set it equal to the slope of our parallel line.

In this case \displaystyle m=5

The slope of our parallel line is \displaystyle 5.

Example Question #1 : How To Identify A Point In Pre Algebra

Define the point based on the coordinate plane.

Number_3

Possible Answers:

\displaystyle (-3,5)

\displaystyle (3,-5)

\displaystyle (3,5)

\displaystyle (-3,-5)

Correct answer:

\displaystyle (3,5)

Explanation:

The point resides in quadrant I (the upper right quadrant), so both values must both be positive. The only possible solution is \displaystyle \small (3,5).

Example Question #6 : How To Identify A Point In Pre Algebra

What is the slope of a line that is perpendicular to \displaystyle y=-15x-31?

Possible Answers:

\displaystyle \frac{1}{5}

\displaystyle -15

\displaystyle \frac{1}{15}

\displaystyle 15

Correct answer:

\displaystyle \frac{1}{15}

Explanation:

The slope of a perpendicular lines has the negative reciprocal of the slope of the original line.

If an equation is in point-slope form, , we use the  from our equation as our original slope.

In this case \displaystyle m=-15

First flip the sign to get \displaystyle m=15

To find the reciprocal you take the integer and make it a fraction by placing a \displaystyle 1 over it. If it is already a fraction just flip the numerator and denominator.

Do this to make the slope \displaystyle m=\frac{1}{15}

The slope of the perpendicular line is \displaystyle \frac{1}{15}.

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=13

\displaystyle m=17

\displaystyle m=4

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 #3 : How To Identify A Point In Pre Algebra

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

Possible Answers:

\displaystyle m=5

\displaystyle m=35

\displaystyle m=15

\displaystyle m=92

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.

Example Question #3 : How To Identify A Point In Pre Algebra

What is the y-intercept of the line \displaystyle y=31x-65?

Possible Answers:

\displaystyle (0,-65)

\displaystyle (31,0)

\displaystyle (-65,0)

\displaystyle (0,31)

Correct answer:

\displaystyle (0,-65)

Explanation:

In the slope-intercept form of a line, , the y-intercept is when the line intersects the y-axis.

It does this at .

So we plug  in for  in our equation

\displaystyle y=31x-65 

to give us

\displaystyle y=31(0)-65

Anything multiplied by  is  so

\displaystyle y=-65

Our coordinates for the y-intercept are \displaystyle (0,-65).

Example Question #4 : How To Identify A Point In Pre Algebra

What is the slope of a line that is parallel to \displaystyle y=16x+17?

Possible Answers:

\displaystyle m=-\frac{1}{16}

\displaystyle m=17

\displaystyle m=-16

\displaystyle m=16

Correct answer:

\displaystyle m=16

Explanation:

Parallel lines have the same slope.

If an equation is in slope-intercept form, , we take the  from our equation and set it equal to the slope of our parallel line.

In this case \displaystyle m=16.

The slope of our parallel line is \displaystyle m=16.

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