Question 443259
Multiply both sides by ab:

{{{ab((x/a) + (y/b)) = 1)}}}
{{{bx + ay = ab}}}
{{{ay = ab-bx}}}
{{{ay = b(a-x)}}}
{{{y = b(1-x/a)}}}
{{{ y = (-b/a)x + b}}}
Then by slope-intercept, b is the y-intercept.
To solve for the x intercept, let y = 0.

{{{0 = (-b/a)x + b}}}
{{{-b = (-b/a)x}}}
{{{-b(-a/b) = x}}}
{{{(cross(-b)*cross(-1)*a)/(cross(b)) = x}}}
{{{a = x}}}

Then a is the x-intercept.