Let f(x) = 2x + 2. Solve f-1(x) when x = 4.

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Question

Let f(x) = 2x + 2. Solve f-1(x) when x = 4.

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zale101 · Answer

the opposite of addition is subtraction so 2x+2 is 2x-2
the opposite of multiplication is division so divide 2 instead of multiplying it by x-2
x-2/2
Answer: f-1(x)= x-2/2
no replace x by 4 and solve :)

zale101 · Answer

now*

anonymous · Answer

im confused

zale101 · Answer

what part?

anonymous · Answer

all of it  lol  whats the answer?

zale101 · Answer

i'll write it algebraically for you
your question is  f(x) = 2x + 2
change f(x) to y
y=2x+2
 solve for x
 y - 2 = 2x
$$\frac{ y-2 }{2 }=x$$

since i already what equals to x, then i'll have to switch x and y, making it equal to y instead of x
$$\frac{ x-2 }{2 }=y$$

now, change y to the inverse function $$f^{-1}(x)$$
$$f^{-1}(x)=\frac{ x-2 }{2 }$$

now, you're question says "when x = 4"
after finding the inverse of the orginial equation, rreplace x with 4
$$f^{-1}(4)=\frac{ (4)-2 }{2 }$$

anonymous · Answer

ohhhh
thank you that helped alot

zale101 · Answer

No Problem :) Glad it did!