why arent x-4 and x-4 inverses of each other???

Question

anonymous · Answer

Assuming you mean "inverse" as in the inverse of a function, suppose $f(x)=x-4$ is indeed the same as its inverse, $f^{-1}(x)$. Then it must have the property that $f\left(f^{-1}(x)\right)=f^{-1}\left(f(x)\right)=x$.

But this clearly isn't the case, since
$$f(x-4)=(x-4)-4=x-8\neq x$$

jhonyy9 · Answer

@mia99 the last term not is +8 bc (-4)*(-4)=16

jhonyy9 · Answer

and so (x-4)*(x+4) not equal x^2 -8 this is equal x^2 -16

ATTENTION please !!!

directrix · Answer

> why arent x-4 and x-4 inverses of each other???

I interpreted the reference to "inverse" as being additive inverse.

A real number and its additive inverse sum to zero.

x-4 and x-4 sum to 2x - 8 which is not zero.

Therefore, they are not additive inverses.

directrix · Answer

>> why arent x-4 and x-4 inverses of each other???

Then, I thought that the question may refer to multiplicative inverses.

A real number (excluding 0) and its multiplicative inverse have a product of one.

(x - 4) * (x - 4) does not equal 1. (x - 4) and (x -4) are not multiplicative inverses.