How do you find equation of a line, L which passes through the point (3, -1) and perpendicular to the line with equation 9x - 3y = 2?
So the slope of the given line is
The slope of a perpendicular line is the negative inverse of the line give. So if
So, in this case the slope of the perpendicular line is
We now have a slope and a point so we can use the point-slope to determine the equation for the perpendicular line.
The point-slope formula states:
Substituting the information we were given and calculated gives:
#y + 1 = -1/3x + 1/3 * 3
or converting to the more familiar point-intercept form gives: