Final answer:
The question asks for an equation to solve for x in triangle PQR, but without additional context about the triangle's properties, selecting an appropriate equation from the provided options is not possible. An equation involving angles in a triangle would align with the sum of angles being 180 degrees, necessitating further information for a precise solution.
Step-by-step explanation:
The student has asked for an equation that can be used to solve for x in triangle PQR. To provide an equation for this, we would typically need more context about triangle PQR, such as angle measurements or side lengths.
However, without further context, we can't definitively choose one of the given options (a-d). Generally, in a geometric context, the sum of angles in a triangle is always 180 degrees, so if x and y represent angles in triangle PQR, then an equation like x + 2y = 180 (scaled up or down) could be relevant. Still, we would need more information to select from the provided options or to see if none of them apply. It is also important to consider that these options could be equations resulting from other scenarios, such as algebraic expressions involving side lengths or other triangle properties. In any case, an equation to solve for x in a triangle would follow the fundamental geometry or algebra principles relevant to the specifics of triangle PQR.