Concept:This is a linear equation involving fractions. Multiply both sides by the LCM of the denominators to eliminate the fractions.Explanation:Start with the equation:51(2+y)=21(y−1)The denominators are 5 and 2. Their LCM is 10.Multiply both sides of the equation by 10:10×51(2+y)=10×21(y−1)This simplifies to:2(2+y)=5(y−1)Expand both sides:4+2y=5y−5Bring the variable terms to one side and the constants to the other side:4+5=5y−2y9=3yDivide both sides by 3:39=yy=3Answer:The solution is y=3, which corresponds to option D.