122. write the equation of the line that is
perpendicular to y = x-5 and passes through
the point (12,-1).

When a line is given in the form

The slope of the line is m. So, in this case, the slope of is 1.

Given a slope , you find the slope of a perpendicular line by imposing

So, if the given line has slope 1, a perpendicular line has slope given by

and thus

So, we want a line with slope -1 and passing through (12,-1). Using the fomula

we get