Roll the Bones: When rolling a pair of dice, the
probability $P$ that the sum of the numbers on those dice is
$x$ is given by
$$P=\frac{6-|7-x|}{36}.$$
Your task is to solve for $x$ in terms of $P$.
Divide your solution into two columns. The left column will contain your calculations.
The right column will contain an explanation of each step.
Your first step will be to simply write down the formula. All subsequent steps must undo only one operation at a time.
Each step will show either (A) an operation performed on both sides, or
(B) a simplification made after performing an operation on both sides.