Dear Ha,
Hi, I’m on holiday in Nha Trang with the Robinsons. We arrived (1) last Saturday. The first day the weather wasn't  (2) very nice, so we did (3)some sightseeing  . I took (4) lots of photographs. On Monday we hired (5) a car and drove (6) out into the country. We stopped (7) for lunch at a lovely little village and then in the afternoon we found (8) a beautiful beach. Last night we went (9) to the cinema. We didn't get back (10) till  about 11p.m., so we got up (11) late this morning and we decide (12) to have a relaxing day by the hotel swimming pool. So that’s where I am now. 

câu 4: a

Tìm x:

\(\dfrac{2}{x-\sqrt{x^2-4}}+\dfrac{2}{x+\sqrt{x^2-4}}=5\)

a,= 𝑥(5𝑥+4)

b, =4x(x² + 6xy - 3y² )

c,=2(𝑥³−7𝑥)

=2𝑥(𝑥²−7)

Tìm x:

\(\sqrt{x^2-4}+\sqrt{x^2-4x+4}=0\)