contestada

Which function is the inverse of f(x) = –5x – 4?
A) f-1(x)=-5x-4
B) f-19(x)=-1/5x+4/5
C) f-1(x) = –4x + 5
D) f-1(x) = 4x + 4

Respuesta :

Just took the test. A is the right answer. 
calculista

Answer:

[tex]f^{-1}(x)=-\frac{1}{5}x-\frac{4}{5}[/tex]

Step-by-step explanation:

we have

[tex]f(x)=-5x-4[/tex]

Let

[tex]y=f(x)[/tex]

[tex]y=-5x-4[/tex]

Step 1

Exchange the variables x for y and y for x

[tex]x=-5y-4[/tex]

Step 2

Isolate the variable y

[tex]x=-5y-4[/tex]

[tex]5y=-x-4[/tex]

[tex]y=-\frac{1}{5}x-\frac{4}{5}[/tex]

Step 3

Let

[tex]f^{-1}(x)=y[/tex]

[tex]f^{-1}(x)=-\frac{1}{5}x-\frac{4}{5}[/tex]

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