Select all lines perpendicular to y−4=−23(x+1)

Answer 1

That equation is in point-slope form:

y - y1 = m(x - x1) where m is the slope

so that slope of that line is -23

line perpendicular to that line will have slope equal to the negative reciprocal of that slope or 1/23.

so all lines perpendicular to that line are all lines with slopes of 1/23.