To make \( p \) the subject of the formula \( y = \frac{a + p}{a - p} \): Start with the equation: \(y = \frac{a + p}{a - p}\) Cross-multiply: \(y(a - p) = a + p\) Distribute \( y \): \(ya - yp = a + p\) Rearrange to isolate terms involving \( p \): \(ya - a = p + yp\) Factor out \( p \) on the right side: \(ya - a = p(1 + y)\) Finally, solve for \( p \): \(p = \frac{ya - a}{1 + y}\) Thus, the formula with \( p \) as the subject is: \(p = \frac{a(y - 1)}{y + 1}\)