f(x)= -x + 1 

"-x + 1" is the sum of -x and 1.

If we take the derivative of x² we get 2x.
But we want -x, not 2x, So we must take the
derivative of  to get -x.

So we need the term .

To get the 1 we must take the derivative of x.

So the function  would be such
a function.

However since the derivative of a constant is zero,
we could have any constant added to that.  So here
are some answers:







Edwin