What is an equation of the line that passes through the point (5,1) and is parallel to the line x+y=9

Answer 1

Parallel means same slope. The slope of x+y = 9 is easier to see as y = -x+9. m = -1 for y = mx +b.

We want a line that passes through (5,1) with a slope of -1. This must be true for any point (x,y) on the line:

(y-1)/(x-5) = -1 This is the equation. You can rearrange it algebraically.