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avatar+1982 

What is the domain of the function f(x) = log (1/x + 12)?

 

A) {x ∈ R}

B) {x ∈ R | x < –12}

C) {x ∈ R | x > –12}

D) {x ∈ R | x ≠ 12}

E) {x ∈ R | x ≠ –12}

 

 

 

Which is equivalent to (-1 + 2i)(5i)?

 

A) -11

B) -8

C) -1 + 7i

D) 10 - 5i

E) -10 - 5i

 Dec 4, 2019
 #1
avatar+129852 
+2

I think this is supposed to be

 

f(x)  =  log   (  1  / ( x + 12) )

 

We cannot take the log  of  0  or a negative.....thus......the domain  is  all real nubers  >  -12   ⇒  "C"

 

 

Second one

 

 (-1  +  2i ) * 5i    =     -5i + 10i^2  =  -5i - 10  =   -10  - 5i

 

 

cool cool cool

 Dec 4, 2019
 #2
avatar+1982 
0

1. Since it is only possible to find the log of a positive number, 1/x + 12 > 0. Therefore, x + 12 > 0, and if 12 is subtracted from both sides, the inequality becomes x > –12, so the domain of the function is {x ∈R| x > –12}.

macabresubwoofer  Dec 5, 2019

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