Question 1076923
i already know what y is, and I only need to find x,

{x+cy=d
{x-dy=c

if we found y, we can find x.

I would solve for y by elimination of the x variable.

 (x + cy) = d
- (x - dy) = -c
x + cy - x + dy = d - c
cy + dy = d - c

y (c + d) = d - c

y = (d - c) / (d + c)

ok,  x - dy = c,
 
x = c + dy

x = c + d* (d - c) / (d + c)

x = c * (d + c)/(d + c)  + d*(d - c)/(d + c)

x = [(cd + c*c) + d*d - cd ] / (d + c)

x = [c*c + d*d ] / (d + c)