(a)[4]
Show that the $x$-coordinate of $P$ satisfies the equation $x = \sqrt{\frac{75e^{-0.2x}}{15 + x}}$.
(b)[2]
Use the equation from part (a) to demonstrate by calculation that the $x$-coordinate of $P$ lies between $1.7$ and $1.8$.
(c)[3]
Apply an iterative formula based on the equation in part (a) to determine the $x$-coordinate of $P$ correct to $4$ significant figures. State the result of each iteration to $6$ significant figures.