cho ΔABC góc ∠A =90 độ,đường cao AH(H thuộc BC).gọi E,F lần lượt là hình chiếu của H lên AB,AC.chứng minh rằng 1. AB.AE=AC.AF=HB.HC 2. AE.EB+AF.FC=AH ² 3. BC ²=3AH ²+BE ²+CF ² 4. tan ³C=BE/CF 5. AB ³/AC ³=BE/CF 6. AB ²/AC ²=HB/HC 7. BC.BE.CF=AH ³ NHANH+ĐÚNG=CTLHN+5*

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I think you should buy _____  pack of mineral water instead. And you can also buy _____  snacks such as potato crisps, 3 kilos of mandarins, 2 kilos of apples, 3 bunches of bananas, ______  cookies and soft candies.

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We should decorate our living room with _____ orange banner. We also need ________  ribbons, balloons, party hats and costume.

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I think that ______ cauliflower is not enough for 3 people. Let’s buy one more.