1) Standard form for writing equations of lines is Ax + By = C, where you can find A, B, and C using two points on the line.
2) Slope-intercept form is y = mx + b, where m is the slope found using two points and b is the y-intercept.
3) The slope of a line perpendicular to another is the opposite reciprocal of the original line's slope. You can find the perpendicular equation using the point-slope formula.