Given Function: We are given the function f(x)=3x−9 and we need to find the inverse function f−1(x) such that f−1(12) gives us the x-value for which f(x)=12. To find the inverse function, we need to solve for x in terms of y, where y=f(x). Let y=3x−9.
Solving for x: Now we will solve the equation y=3x−9 for x. Add 9 to both sides of the equation to isolate the term with x on one side. y+9=3x
Finding Inverse Function: Next, divide both sides of the equation by 3 to solve for x. 3y+9=xThis gives us the inverse function f−1(y)=3y+9.
Substitute y with 12: Now we can find f−1(12) by substituting y with 12 in the inverse function.f−1(12)=3(12+9)
Perform Addition: Perform the addition inside the parentheses. f−1(12)=3(21)
Final Result: Finally, divide 21 by 3 to get the value of f−1(12).f−1(12)=7
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