Please, I am begging. I don't understand inverses.

0

9

-2

-23

Step-by-step explanation:

a function f(x) defines a y-value for any valid x-value.

that's why it is often written as y = f(x).

the inverse function of an original function just turns the question upside down.

now we want to see for a given y-value of the original function, what was the original x-value to get this y.

therefore we try to transform the original equation that calculates y out of x into one that calculates x out of y.

so, in our example

f(x) = y = -4x - 3

4x + y = -3

4x = -y - 3

x = (-y - 3) / 4

in order to keep the usual terminology with functions also for inverse functions, which are in the end nothing else than functions again, we then name the input variable "x" again, and the result "y".

so, the inverse function is therefore as a function of x

y = (-x - 3) / 4

for x = -3, y = (--3 - 3) / 4 = (3-3) / 4 = 0

when we have y for the inverse function looking for its corresponding x value, then we are investing the inverse function and come back to the original function.

so, for y=-3 of the inverse function that means x=-3 for the inverse inverse (or original) function looking for the y, which is then the x of the inverse function.

f(-3) = -4×-3 - 3 = 12 - 3 = 9 = x of the inverse function.

for x=5 of the inverse function, y = (-5-3)/4 = -8/4 = -2

for y=5 of the inverse function that means x=5 for the inverse inverse (or original) function looking for the y, which is then the x of the inverse function.

f(5) = -4×5 - 3 = -20 - 3 = -23 = x of the inverse function.

step-by-step explanation:

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