Parallel lines have the same slope. To write the equation of a parallel line, first find the slope (m) of the original line by rewriting its equation in y=mx+b form. Then use the same m value and a new given point (x,y) to write the parallel line's equation in y=mx+b form by solving for b. For example, to find the equation of a line parallel to 2x-3y=17 through the point (9, -3), first get the original line in y=mx+b form to find m, then use m and (9, -3) to write the parallel line's equation.
2. PARALLEL LINES
• Parallel lines have the same slope
• To find the slope, put the equation in y=mx+b
• Use m and the new given point to write a new equation
3. EXAMPLE
• Write the equation of a line parallel to 2x-3y=17 and goes through the point (9, -3).
• Hint: Get the equation in y=mx+b. Plug m and (9, -3) in y=mx+b. Find b.
5. IF IT IS PERPENDICULAR
• If the question wants the perpendicular line, find the slope, flip it and change the
sign. Then do exactly what we did with the parallel equation.
