1. The problem statement, all variables and given/known data Find the equation of the horizontal components of two strings tied to a painting at 45 degree angles with the horizontal. 2. Relevant equations Fnet = 0 3. The attempt at a solution Since the painting is in equilibrium, I found that, in the horizontal direction, Fnet = 0 = S1x - S2x, where S1x S2x are the horizontal components of the force by the strings. What I don't understand is why S1x = S2x. This naturally follows as a result, but aren't these two quantities equal and opposite, since they have the same magnitude but are in opposing directions? Shouldn't it be S1x = -S2x?