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avatar+1275 

Manu needs to determine whether x + 4 is a factor of f(x)=−x^4−6x^3+15x−72 .

How can Manu use the factor theorem to determine whether x + 4 is a factor of f(x) ?

 

Drag a value, expression, or phrase into each underline to correctly complete the statements.

Manu evaluates  ________   and determines its value to be  _______ . Manu concludes that x + 4 ______ a factor of f(x)=−x^4−6x^3+15x−72 . 

 

 

The options are f(-4) , -4 , f(0 ), f(4) ,-652 , -72 ,is , is not

 

I think it should be f(-4) ,-4 , and is not

 Sep 12, 2019
 #1
avatar+10536 
+2

(x+4) is not.

laugh

 Sep 12, 2019
 #4
avatar+1275 
0

thank you!smiley

jjennylove  Sep 12, 2019
 #2
avatar+103858 
+1

Manu needs to determine whether x + 4 is a factor of f(x)=−x^4−6x^3+15x−72 .

How can Manu use the factor theorem to determine whether x + 4 is a factor of f(x) ?

 

If x + 4 is a factor, then x = -4  is a root.....use synthetic division....if we get a 0, then x + 4  is a factor....so

 

-4  [ -1       -6         0         15       -72  ]

                  4          8        -32        68

     ____________________________

       -1      -2          8        -17        -4

 

We have a remainder of -4, so..  x = -4  is not a root and ..x + 4  is NOT a factor

 

 

 

cool cool cool

 Sep 12, 2019
 #3
avatar+1275 
+1

Awesome, so I inputted it correct?

Manu evaluates  f(-4)  and determines its value to be  -4 . Manu concludes that x + 4 is not a factor of f(x)=−x^4−6x^3+15x−72 .

 

Like this ?

jjennylove  Sep 12, 2019
 #5
avatar+103858 
+1

Exactly   ....!!!

 

If   f(a)   produces anything but a "0"....then "a"  is not a root  and  (x - a)  is not a factor....

 

 

 

cool cool cool

CPhill  Sep 12, 2019

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