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How do you find the range and intercepts of the function f(x)=4|x+5| ?

 Sep 17, 2017
edited by medlockb1234  Sep 17, 2017

Best Answer 

 #1
avatar+2446 
+2

The range is the set of all possible outputs that a function can produce. 

 

f(x)=4|x+5|

 

The absolute value of any number will can result in a positive number or 0, and 4 multiplied by a positive number or 0 does not change this property at all. Therefore, the range is the following:

 

Range:{R|y0}

 

This means that the range can be all nonnegative numbers. In interval notation, it would look like the following:

 

Range:[0,+)

 

How do we find the intercepts? To do it without a graph, you can figure out by setting x=0 and y=0 and solving in each case. Let's do that.

 

y=4|x+5| Plug in 0 for x. This time, we are solving for the y-intercept.
y=4|0+5| Simplify inside the absolute value first.
y=4|5|  
y=45=20 We have now determined the coordinates of the y-intercept.
(0,20) This is the exact coordinates of the y-intercept.
   

 

Let's do the exact same process. This time, however, we set y=0 to find the x-intecept.

 

y=4|x+5| Set y equal to 0.
0=4|x+5| Divide by 4 on both sides.
0=|x+5| The absolute value always splits an equation into its plus or minus. However, 0 is neither positive nor negative, so there aren't 2 equations that one can set up.
x+5=0  
x=5 We have now determined the x-intercept, as well.
(5,0)  
   
 Sep 17, 2017
 #1
avatar+2446 
+2
Best Answer

The range is the set of all possible outputs that a function can produce. 

 

f(x)=4|x+5|

 

The absolute value of any number will can result in a positive number or 0, and 4 multiplied by a positive number or 0 does not change this property at all. Therefore, the range is the following:

 

Range:{R|y0}

 

This means that the range can be all nonnegative numbers. In interval notation, it would look like the following:

 

Range:[0,+)

 

How do we find the intercepts? To do it without a graph, you can figure out by setting x=0 and y=0 and solving in each case. Let's do that.

 

y=4|x+5| Plug in 0 for x. This time, we are solving for the y-intercept.
y=4|0+5| Simplify inside the absolute value first.
y=4|5|  
y=45=20 We have now determined the coordinates of the y-intercept.
(0,20) This is the exact coordinates of the y-intercept.
   

 

Let's do the exact same process. This time, however, we set y=0 to find the x-intecept.

 

y=4|x+5| Set y equal to 0.
0=4|x+5| Divide by 4 on both sides.
0=|x+5| The absolute value always splits an equation into its plus or minus. However, 0 is neither positive nor negative, so there aren't 2 equations that one can set up.
x+5=0  
x=5 We have now determined the x-intercept, as well.
(5,0)  
   
TheXSquaredFactor Sep 17, 2017

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