32
24
56
48
a7b2c3d5=512=29 AM≥G.M a7+2b2+2c3+2d54≥4√a7⋅2b2⋅2c3⋅2d5 a7+2b2+2c3+2d54≥4√212 a7⋅2b2⋅2c3⋅2d5≥8.4 ≥32