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

Options:
-x + y = 2
-x – y = 2
x – y = 2
-x – y = 0
x + y = 0

Question

What is the equation of the line that is perpendicular to -x + y = 7 and passes through (-1, -1)?

Options:
-x + y = 2
-x – y = 2
x – y = 2
-x – y = 0
x + y = 0

anonymous · Answer

Perpendicular lines have slopes that are negative reciprocals of one another.  To find the slope of a line in standard form (Ax + By = C), use the formula m = -A/B to find the original slope, then flip the sign and flip the fraction for the perpendicular slope.  Then we can proceed.