Math problem of grade three: how long and how long does it take to make a rectangular window frame with 6 meters of aluminum alloy material to make the window cabinet transparent?
Let this window be x meters long and y meters wide, then 3x+2y = 63x+2y ≥ 2 √ [(3x) * (2y)] = 2 √ (6xy) When 3X=2Y=3 ≥ take the equal sign, that is, 2 √ (6xy) ≤ 6 √ (6xy) ≤ 3 6xy ≤ 9 xy. ...