Chỉ dùng thêm quỳ tím hãy nhận biết các dd riêng biệt bị mất nhãn sau: Na2CO3,Na2SO4,CH3COONa,Ba(NO3)2,CH3COOH,,H2SO4 loãng.

Nhận biết hcl naoh back2 na2so4 k dùng quỳ tím

Giải hệ phương trình {x+3y=4

{2x+5y=7

Giải phương trình x mũ 2 - 5x + 3 = 0

Choose the best answer.

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.

Choose the best answer.

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

Choose the best answer.

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