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Find the inverse f(x)=x+5/3x-1

f^-1(x)=

User Stephzcj
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Answer:

  • f^-1(x) = (3/8)(x +1) . . . . as written
  • f^-1(x) = (x +5)/(3x -1) . . . with appropriate parentheses

Explanation:

The inverse function can be found by solving for y:

x = f(y)

x = y + 5/3y -1 . . . . . . . . . . y +(5/3)y -1 . . . per order of operations

x+1 = 8/3y . . . . . . . . . . add 1

(3/8)(x +1) = y . . . . . . . . multiply by 3/8

f^-1(x) = (3/8)(x +1) . . . . . inverse of the function as written

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Perhaps you intend f(x) = (x+5)/(3x-1). The inverse is found the same way.

x = (y +5)/(3y -1)

x(3y -1) = y +5

3xy -x = y +5 . . . . . eliminate parentheses

3xy -y = x + 5 . . . . . add x-y

y(3x -1) = x +5 . . . . . factor out y

y = (x +5)/(3x -1) . . . divide by the coefficient of y

f^-1(x) = (x +5)/(3x -1) . . . . inverse of rational function

User Leonard Ge
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