中二數題=====x=5-2y/y-1+3.......

a = (p + t) / (s - t)
as - at = p + t
as - p = t + at
as - p = t(1 + a)
t = (as - p) / (1 + a)


ab + c(b + 1) = a
ab + cb + c = a
b(a + c) = a - c
b = (a - c) / (a + c)


x/a + 1/(y - b) = 1/a
x(y - b) + a = y - b ..............multiple both side by a(y - b)
xy - bx + a = y - b
b - bx = y - a - xy
b(1 - x) = y(1 - x) - a
b = y - a/(1 - x)


x = (5 - 2y) / (y - 1) + 3
x(y - 1) = 5 - 2y + 3(y - 1)
xy - x = 5 - 2y + 3y - 3
xy - y = x + 2
y(x - 1) = x + 2
y = (x + 2) / (x - 1)

some answer is wrong.
the method is very strange

a = (p + t) / (s - t) ---------------(t)
as - at = p + t
as - p = t + at
as - p = t(1 + a)
t = (as - p) / (1 + a)

ab + c (b + 1) = a ----------------(b)
ab + cb + c = a
b(a + c) = a - c
b = (a - c) / (a + c)

x / a + 1 / (y - b) = 1 / a -----------------(b)
[x /a + 1 / (y - b)] * [a(y - b)] = 1 /a * a(y - b)
x (y - b) + a = y - b
xy - bx + a = y - b
b - bx = y - a - xy
b (1 - x) = y (1 - x) - a
b = y - a / (1 - x)

x = (5 - 2y) / (y - 1) + 3 ---------------(y)
x(y - 1) = 5 - 2y + 3(y - 1)
xy - x = 5 - 2y + 3y - 3
xy - y = x + 2
y(x - 1) = x + 2
y = (x + 2) / (x - 1)

小學教的，加變減乘變除
a = (p + t) / (s - t) -> as - at = p + t-> at + t = as - p
t (a + 1) = as - p -> t = (as -p)/(a + 1)