I am also far from a math scholar, so my terminology and knowledge may not be great.

I would like to plot a smooth line from 0,0 to 100,100 that intercepts (b), where b is on a line from (x=100-y). see below

Essentially, I am looking for (x), where (y) and (b) is given.

(y) is 0 - 100

(b) is (x) where (x = 100-y)

for example. where (y = 90) and (b = 10), (x) will equal 10.

but if (y = 70) and (b = 10), what is x?

In the end, I would love an equation that is something like (x = y something something b something something), for example.

I hope I have explained this well. And highly appreciate any help.

fyi, if the picture attached needs to be better quality, I can redraw. just ask. Thanks.