vijaykramesh/khan-exercises — comment on commit 09c612efe0061e0bfac0941e64089267c92b5d01
File: exercises/converting_between_point_slope_and_standard_form.html line 56
By smenks13:

I think you need to have another hint before this one that demonstrates going through the motions of plugging x1 back into the equation in standard form, and solving for y1.