Algebra II : Linear Functions

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #31 : Transformations Of Linear Functions

Shift the graph \displaystyle 2x+3y = 6 down six units.  What is the new equation?

Possible Answers:

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

\displaystyle y=-\frac{2}{3}x-16

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

\displaystyle y=-\frac{2}{3}x+6

\displaystyle y=-\frac{2}{3}x-8

Correct answer:

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

Explanation:

Rewrite the given equation in standard form to slope-intercept form.

\displaystyle y=mx+b

Subtract \displaystyle 2x from both sides.

\displaystyle 2x+3y -2x= 6-2x

\displaystyle 3y=-2x+6

Divide by three on both sides.

\displaystyle \frac{3y}{3}=\frac{-2x+6}{3}

Simplify this equation.

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

Shifting this equation down means that the y-intercept will be subtracted six.

\displaystyle y=-\frac{2}{3}x+2-6

The answer is:  \displaystyle y=-\frac{2}{3}x-4

Example Question #82 : Linear Functions

Translate the graph \displaystyle y=10-2x down fifteen units.  What is the new equation?

Possible Answers:

\displaystyle y=-2x-5

\displaystyle y=-13x+10

\displaystyle y=-2x-25

\displaystyle y=-2x+25

\displaystyle y=-2x+5

Correct answer:

\displaystyle y=-2x-5

Explanation:

The given equation can be rewritten in slope-intercept format, \displaystyle y=mx+b.

\displaystyle y=10-2x \rightarrow y=-2x+10

Shifting down a line fifteen units will decrease the y-intercept by 15.

\displaystyle y=-2x+10-15

The answer is:  \displaystyle y=-2x-5

Example Question #83 : Linear Functions

Translate the graph \displaystyle y=2x+5 left four units and up one unit.  What's the new equation?

Possible Answers:

\displaystyle y= 2x-17

\displaystyle y= 2x-3

\displaystyle y= 2x-7

\displaystyle y= 2x+14

\displaystyle y= 2x+8

Correct answer:

\displaystyle y= 2x+14

Explanation:

Shifting the equation up one unit will change the y-intercept by adding one.

\displaystyle y=2x+5+(1) = 2x+6

If the graph is to be shifted four units to the left, the x-variable will need to be replaced with the quantity \displaystyle (x+4).

\displaystyle y=2(x+4)+6

Use the distribution property to simplify the binomial.

\displaystyle y=2x+8+6 = 2x+14

The equation is:  \displaystyle y= 2x+14

Example Question #891 : Algebra Ii

Shift the function \displaystyle x+3y=6 up four units.  What is the new equation?

Possible Answers:

\displaystyle y=-\frac{1}{3}x+\frac{3}{10}

\displaystyle y=-\frac{1}{3}x+6

\displaystyle y=-3x+6

\displaystyle y=-\frac{1}{3}x+\frac{16}{3}

\displaystyle y=-3x+\frac{16}{3}

Correct answer:

\displaystyle y=-\frac{1}{3}x+6

Explanation:

Rewrite this equation in standard form to slope intercept format.

Subtract \displaystyle x on both sides.

\displaystyle x+3y-x=6-x

\displaystyle 3y=-x+6

Divide by three on both sides.

\displaystyle \frac{3y}{3}=\frac{-x+6}{3}

Simplify this equation.

\displaystyle y=-\frac{1}{3}x+2

If this graph is shifted up four units, simply add four to the y-intercept.

\displaystyle y=-\frac{1}{3}x+2+4

The answer is: \displaystyle y=-\frac{1}{3}x+6

Example Question #85 : Linear Functions

Shift \displaystyle y=6x-4 left eight units.  What is the new equation?

Possible Answers:

\displaystyle y= 6x-52

\displaystyle y= 6x+12

\displaystyle y= 6x+44

\displaystyle y= -2x+44

\displaystyle y= 6x-36

Correct answer:

\displaystyle y= 6x+44

Explanation:

Shifting the graph left 8 units will require changing the x-variable to \displaystyle (x+8).

Replace the term and simplify the equation.

\displaystyle y=6(x+8)-4

Distribute the six through the binomial.

\displaystyle y=6x+48-4 = 6x+44

The equation is:  \displaystyle y= 6x+44

Example Question #86 : Linear Functions

Translate the function \displaystyle y=3-9x left 5 units.  What is the new equation?

Possible Answers:

\displaystyle y=-9x+46

\displaystyle y=-9x-42

\displaystyle y=-9x-15

\displaystyle y=-9x-62

\displaystyle y=-9x+18

Correct answer:

\displaystyle y=-9x-42

Explanation:

If the graph is shifted leftward, apply the transformation by replacing the x-variable with \displaystyle (x+5).

\displaystyle y=3-9(x+5)

Simplify this equation by distribution, and rewrite this in slope intercept format.

\displaystyle y=3-9x-45

Combine like-terms.

The answer is:  \displaystyle y=-9x-42

Example Question #87 : Linear Functions

Translate the line \displaystyle y= 7-3x down three units and left four units.  What is the new equation?

Possible Answers:

\displaystyle y= -3x+8

\displaystyle y= -3x-12

\displaystyle y= -3x-8

\displaystyle y= -3x+16

Correct answer:

\displaystyle y= -3x-8

Explanation:

Rewrite the equation in slope-intercept form:  \displaystyle y=mx+b

\displaystyle y=-3x+7

Shifting this line down three units will decrease the y-intercept by three.

\displaystyle y=-3x+7-(3) = -3x+4

\displaystyle y= -3x+4

If the line is shifted left four units, the x-variable will need to be replaced with \displaystyle (x+4).

\displaystyle y= -3(x+4)+4

Simplify this equation.

\displaystyle y=-3x-12+4 = -3x-8

The answer is:  \displaystyle y= -3x-8

Example Question #88 : Linear Functions

Translate the line \displaystyle x-y=0 left three units and down four units.  What is the new equation?

Possible Answers:

\displaystyle y=x+2

\displaystyle y=x-7

\displaystyle y=-x+3

\displaystyle y=-x-6

\displaystyle y=x-1

Correct answer:

\displaystyle y=x-1

Explanation:

Rewrite the given equation in standard form to slope-intercept form.

Add \displaystyle y on both sides.

\displaystyle x-y+y=0+y

\displaystyle y=x

A shift down four units will decrease the y-intercept by four.  The current y-intercept is zero.  Rewrite the equation.

\displaystyle y=x-4

The line shifted three units to the left means that the x-variable will need to be replaced with \displaystyle (x+3).

Rewrite the equation.

\displaystyle y=(x+3)-4

Simplify this equation.

The answer is:  \displaystyle y=x-1

Example Question #371 : Functions And Graphs

Translate the graph \displaystyle y=-3(-x+8) up three units.  What is the new equation?

Possible Answers:

\displaystyle y= 3x-24

\displaystyle y= 3x-33

\displaystyle y= 3x-21

\displaystyle y= 3x+15

\displaystyle y= 3x+33

Correct answer:

\displaystyle y= 3x-21

Explanation:

Simplify the equation by distribution.

\displaystyle y=-3(-x+8) = (-3)(-x)+(-3)(8) = 3x-24

Shifting this line up by three units will add three to the y-intercept.

\displaystyle y= 3x-24+3 = 3x-21

The answer is:  \displaystyle y= 3x-21

Example Question #371 : Functions And Graphs

Shift the graph:  \displaystyle y=2(2x+3) up five units.  What is the new equation?

Possible Answers:

\displaystyle y =4x+15

\displaystyle y =4x+11

\displaystyle y =4x+8

\displaystyle y =4x+10

\displaystyle y =4x+18

Correct answer:

\displaystyle y =4x+11

Explanation:

Use distribution to simplify this equation.  We will need to put the equation in slope-intercept format, \displaystyle y=mx+b

\displaystyle y=2(2x+3) =2(2x)+2(3) =4x+6

The equation becomes:  \displaystyle y =4x+6

Shifting this equation up five units will add five to the y-intercept.

The answer is:  \displaystyle y =4x+11

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