a, \(\sqrt{121}-2\sqrt{16}\)= \(11-8\) = 3

b\(\sqrt{61^2-60^2}\) = \(\sqrt{\left(61+60\right)\left(61-60\right)}\) = \(\sqrt{121.1}\) = 11

c, \(\sqrt{\left(\sqrt{5}-2\right)^2}\) = \(\left|\sqrt{5}-2\right|=\sqrt{5}-2\)

d, \(2\sqrt{32}+\sqrt{98}-3\sqrt{18}=2.4\sqrt{2}+7\sqrt{2}-3.3\sqrt{2}=8\sqrt{2}+7\sqrt{2}-9\sqrt{2}=6\sqrt{2}\)

a, \(A=\left(\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\dfrac{\sqrt{x}-1}{\sqrt{x}+1}\right)\left(1-\dfrac{1}{\sqrt{x}}\right)\left(đkxđ:x>0,x\ne1\right)\)

\(A=\left(\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\right)\left(\dfrac{\sqrt{x}}{\sqrt{x}}-\dfrac{1}{\sqrt{x}}\right)\)

\(A=\left(\dfrac{x+2\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\right)\left(\dfrac{\sqrt{x}-1}{\sqrt{x}}\right)\)

\(A=\left(\dfrac{\left(\sqrt{x}+1\right)^2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\right)\dfrac{\sqrt{x}-1}{\sqrt{x}}\)

\(A=\dfrac{\sqrt{x}+1}{\sqrt{x}}\)

b, A=1

\(\Leftrightarrow\dfrac{\sqrt{x}+1}{\sqrt{x}}=1\)

\(\Rightarrow\sqrt{x}+1=\sqrt{x}\)

\(\Leftrightarrow\sqrt{x}-\sqrt{x}+1=0\)

\(\Leftrightarrow1=0\) ( vô lý)

vậy không có giá trị của x để A=1

Read the passage carefully then answer True or False

Young generation nowadays enjoys fashion clothing especially jeans. Ao dai has been interested by designers and most of people. Ao dai has been also a traditional and favorite dress of Vietnamese people. But now many people like wearing modern clothing at work because it is not only convenient but also comfortable, especially jeans. In the past, many workers and students liked wearing jeans because they were strong, cheap and fashionable. However, a lot of people continue wearing Ao dai. It is traditional, fashionable and also modern anyway. It has not been out of fashion in spite of the increasing or decreasing of the worldwide economy

Question: Modern clothing is both convenient and comfortable.

a. True

b. False

Không giải phương trình, hãy cho biết mỗi phương trình sau có bao nhiêu nghiệm?

a ) 15 x 2 + 4 x − 2005 = 0 b ) − 19 5 x 2 − 7 x + 1890 = 0