Question

Given the graph of a line y=−x. Write an equation of a line which is parallel and goes through the point (8,2).

Answer 1

The slope of y = -x is m = -1.  Thus, starting with the slope-intercept form y = mx + b, we substitute -1 for m, 8 for x and 2 for y, to determine the vaue of b:

2 = -1(8) + b, or 10 = b.  Then the equation of the line parallel to y = -x and passing thru (8,2) is:

y = -x + 10.