Question

What is the equation of the line perpendicular to –x + y = 7 and passing through (-1, -1)?

Answer 1

- x + y = 7
y = x + 7
slope = 1
perpendicular slope = -1

at point (-1, -1),
y = mx + c
-1 = -1 (-1) + c
-1 = 1 + c 
c = -1 -1
c = - 2

equation:
y = -x -2
y + x = -2 or - x - y = 2