Question 249801
   -4x - 5y = 6
=> -5y = 4x + 6
=> {{{y = -4x/5 - 6/5}}}

The above equation is in the form of 

y = mx + c

Where m is the slope of the line.

On comparison we see that {{{m = -4/5}}}. Thus the slope of the given line is {{{-4/5}}}.

Now a line parallel to the given line will have the same slope i.e {{{-4/5}}}

The slope of a perpendicular line will be the negative reciprocal i.e {{{5/4}}}