Concept:Simplify complex linear equations by first handling the inner bracket, then clearing denominators to solve for x.Explanation:First, simplify inside the bracket: 2x−21−x=24x−(1−x)=25x−1.Now the equation becomes: 47x−1−31⋅25x−1=310.This simplifies to: 47x−1−65x−1=310.Multiply every term by the LCM 12: 3(7x−1)−2(5x−1)=40.Expand: 21x−3−10x+2=40.Combine like terms: 11x−1=40.Solve: 11x=41, so x=1141.Now find 211x+21=241+21=262=31.Answer:B. 31