How do you write the equation of a line in point slope form that is parallel to #y= -1x+2# and goes through (8,-7)?

1 Answer
May 9, 2015

The solution is #y= -x + 1#.

The reason is the following:
Since the line searched is parallel to #y=-x+1# it must have the same slope than this one, that is, the same quoeficient in x, so it must be of the form #y=-x+b#, being b an unknown number.
Now, because the line searched goes through the point (8,-7), being "8" the coordinate "x" and "-7" the coordinate "y", its equation must satisfy #-7=-8+b# and immediately you obtain that #b=1#, so the equation of the line searched is #y=-x+1#.