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If f(x) = 5x, what is f–1(x)?

User Tysonjh
by
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1 Answer

3 votes
Answer: f⁻¹ (x) =
(x)/(5)
;
___________________________________________________________
→ or; write as: f⁻¹ (x) =
(1)/(5) x
.
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Step-by-step explanation:
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Given: " f(x) = 5x " ; Find: " f⁻¹ (x) " ;

Note that: " f⁻¹ (x) " is the "inverse function".
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Given: " f(x) = 5x " ;

Rewrite as: " y = 5x" ;

To solve for the "inverse function" ; exchange "x" with "y"; and "y" with "x" ; and rewrite:
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→ x = 5y ;
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Now, isolate "y" on one side of the equation; & solve for "y" ; in terms of "x" ;

x = 5y ;

5y = x ;

Divide EACH SIDE of the equation by "5" ; as follows:

5y / 5 = x / 5 ;

to get:
___________________________________________________________
y = x / 5 ;
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Now, replace the "y" ; with: " f⁻¹ (x) " ;

→ and rewrite; as follows:
___________________________________________________________

f⁻¹ (x) =
(x)/(5)
;
___________________________________________________________

or, write as:
___________________________________________________________

f⁻¹ (x) =
(1)/(5) x
.
___________________________________________________________
User Jah
by
9.1k points