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Let f:R -{3} to R{1} : f(x) = (x-2)/(x-3...

Let `f:R -{3} to R{1} : f(x) = (x-2)/(x-3)and g:R to R , g(x)=2x-3 and f^-1(x)+g^-1(x)=13/2` then sum of all value of x is

A

2

B

3

C

5

D

7

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the values of \( x \) such that \( f^{-1}(x) + g^{-1}(x) = \frac{13}{2} \), where \( f(x) = \frac{x-2}{x-3} \) and \( g(x) = 2x - 3 \). ### Step 1: Find the inverse of \( f(x) \) Let \( y = f(x) = \frac{x-2}{x-3} \). Cross-multiplying gives: \[ y(x - 3) = x - 2 \] This simplifies to: \[ yx - 3y = x - 2 \] Rearranging terms, we have: \[ yx - x = 3y - 2 \] Factoring out \( x \) from the left side: \[ x(y - 1) = 3y - 2 \] Thus, we can express \( x \) in terms of \( y \): \[ x = \frac{3y - 2}{y - 1} \] Therefore, the inverse function is: \[ f^{-1}(y) = \frac{3y - 2}{y - 1} \] Replacing \( y \) with \( x \): \[ f^{-1}(x) = \frac{3x - 2}{x - 1} \] ### Step 2: Find the inverse of \( g(x) \) Let \( a = g(x) = 2x - 3 \). Rearranging gives: \[ a + 3 = 2x \implies x = \frac{a + 3}{2} \] Thus, the inverse function is: \[ g^{-1}(a) = \frac{a + 3}{2} \] Replacing \( a \) with \( x \): \[ g^{-1}(x) = \frac{x + 3}{2} \] ### Step 3: Set up the equation We have: \[ f^{-1}(x) + g^{-1}(x) = \frac{13}{2} \] Substituting the inverse functions: \[ \frac{3x - 2}{x - 1} + \frac{x + 3}{2} = \frac{13}{2} \] ### Step 4: Clear the fractions To eliminate the fractions, multiply through by \( 2(x - 1) \): \[ 2(3x - 2) + (x + 3)(x - 1) = 13(x - 1) \] Expanding each term: \[ 6x - 4 + (x^2 + 3x - x - 3) = 13x - 13 \] This simplifies to: \[ 6x - 4 + x^2 + 2x - 3 = 13x - 13 \] Combining like terms: \[ x^2 + 8x - 7 = 13x - 13 \] Rearranging gives: \[ x^2 - 5x + 6 = 0 \] ### Step 5: Factor the quadratic equation Factoring: \[ (x - 2)(x - 3) = 0 \] Thus, the solutions are: \[ x = 2 \quad \text{and} \quad x = 3 \] ### Step 6: Find the sum of all values of \( x \) The sum of the values of \( x \) is: \[ 2 + 3 = 5 \] ### Final Answer The sum of all values of \( x \) is \( \boxed{5} \).
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