mot nha` giao' su o~ bang cali vi thanh da~ c/m toan' 9>11
bai` chung' minh nhu sau
TA CO' 0.09 > 0.011 (1) BOI~ VI` 0.09 - 0.011 >0
TA CO' THE DAT X=9 , Y=11
(1) <=> 0.0X >0.0Y (2)
TA CHIA 2 VE' (2) CHO O.O1
(2)<=> 0.0X/0.01 > 0.0Y/0.01
<=> X > Y MA` X=9 , Y=11
VAY 9 > 11 (DUONG` PHO CHEU MUA)