✓ Mathematica : cpu = 1.12565 (sec), leaf count = 50
DSolve[Derivative[2][y][x] == -((alpha*(a - b)^2*beta*y[x])/((-a + x)^2*(-b + x)^2)) - (((1 + alpha + beta)*(-a + x)^2*(-b + x) + (1 - alpha - beta)*(-a + x)*(-b + x)^2)*Derivative[1][y][x])/((-a + x)^2*(-b + x)^2),y[x],x]
✓ Maple : cpu = 0.079 (sec), leaf count = 39
dsolve(diff(diff(y(x),x),x) = -((alpha+beta+1)*(x-a)^2*(x-b)+(1-alpha-beta)*(x-b)^2*(x-a))/(x-a)^2/(x-b)^2*diff(y(x),x)-alpha*beta*(a-b)^2/(x-a)^2/(x-b)^2*y(x),y(x))