P= x+y / x-y how do I solve for y
Let us put in some brackets.
P = (x + y) / (x - y)
multiply both sides by (x - y).
P(x - y) = x + y
multiply out the lhs.
Px - Py = x + y
put the x-terms on the lhs and the y-terms on the rhs.
Px - x = y + Py
Take out common factors on both sides.
(P - 1)x = y(1 + P)
divide both sides by (1 + P)
x(P - 1)/(P + 1) = y
Answer: y = x.(P - 1)/(P + 1)