giải phương trình

a,\(\dfrac{1}{x+\sqrt{1+2x^2}}+\dfrac{1}{x-\sqrt{1+x^2}}=-2\)

\(\sqrt{x+\sqrt{2x-1}}+\sqrt{x-\sqrt{2x-1}}=\sqrt{2}\)

Giải phương trình

a,1+\(\sqrt{3x+1}\)=3x

b,\(\sqrt{2+\sqrt{3x-5}}\)=\(\sqrt{x+1}\)

c,\(\sqrt{\dfrac{5x+7}{x+3}}\)=4

d,\(\dfrac{\sqrt{5x+7}}{\sqrt{x+3}}\)=4

1 4   :   x   =   1 2 , x có giá trị là

A. 2 1

B. 1 2

C. 1 8

D. 8 1

So sánh phần diện tích gạch sọc và phần diệc tích để trắng trong hình bên

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions

The Internet has enabled most people to get contact in a matter of moment

A.  Most of people have been able to get in contact by the Internet in a matter of moments.

B.  Most of people have got in contact as  enable in a matter of moments by the Internet

C. On the Internet, most of people are able to get in contact a matter of moments.

D. On the Internet, most of people can find their contact a matter of moments