Question

How do you determine the missing coordinate A (0, d), B(d, 0) if slope is 0?

Answer 1

No solution is possible.

Explanation:

Two point coordinates: `color(blue)(""(x_1,y_1))` and `color(red)(""(x_2,y_2))`
have a slope of `color(magenta)0` if and only if `color(blue)(y_1)=color(red)(y_2)`

Given the points `color(blue)(A: (0,d))` and `color(red)(B: (d,0))`
this means that `color(blue)d=color(red)0`
and since (presumably) `color(red)d=color(blue)d`
the given points are actually `color(blue)(A: (0,0))` and `color(red)(B: (0,0))`

The given points are actually the same point.

In calculating the slope we would have
`color(white)("XXX")"slope"=(color(red)(y_2)-color(blue)(y_1))/(color(red)(x_2)-color(blue)(x_1))=0/0` an undefined value;
and therefore it can not be equal to the stated value of `color(magenta)0`