A few days ago
Dragon

Inverse functions?

I’m looking at an example problem and I’m confused. The question is: Which of the functions is the inverse function of f(x)=5/x-2?

The answer is h(x)=5/x+2 but I keep getting x/5+2.

f(x)=5/x-2

y=5/x-2

x=5/y-2

x/5=y-2

x/5+2=y

What process am I doing incorrectly?

Top 2 Answers
A few days ago
Anonymous

Favorite Answer

Step 3 to step 4:

x = 5/(y – 2)

y – 2 = 5/x, not x/5

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A few days ago
Kay B
To find the inverse you need to

1. write the equation with y, f(x) =y

y=5 / x-2

2. Interchange x and y

x =5 /y-2

3. Then make y the subject again

cross-multiply

x(y-2)=5

xy-2x=5

xy=5+2x

y=5+2x /x

which is

y=5/x +2x/x

y=5/x + 2

The problem is in your fourth line. You cannot move the 5 the way you are. Check the answer again.

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