(1-2y)(1-2y)-4(2y-1)(3y-1)≥0
1-4y+4y^2-4(6y^2-5y+1)≥0
1-4y+4y^2-24y^2+20y-4≥0
-20y^2+16y-3≥0
y ∈[3/10 1/2 ]