Question 362834
Use the intercept form of the equation:  {{{x/a +y/b = 1}}}.  Since the x- and y-intercepts are equal, a = b, so the equation becomes
{{{x/a + y/a = 1}}}.  Substitute the coordinates of the given point into this equation:
{{{6/a + -8/a = 1}}},
{{{-2/a = 1}}}, or a = -2.  Therefore the equation is
{{{-x/2-y/2 = 1}}}.