Question

Giải giúp em vs ạ. Em xin cảm ơn o(︶︿︶)o

Answer 1

Bài 1: 

a) Ta có: \(A=3\sqrt{49}-\sqrt{25}\)

\(=3\cdot7-5\)

=21-5=16

b) Ta có: \(B=\sqrt{\left(3-2\sqrt{5}\right)^2}-\sqrt{20}\)

\(=2\sqrt{5}-3-2\sqrt{5}\)

=-3

Answer 2

Bài 2: 

a) Ta có: \(P=\left(\dfrac{\sqrt{x}}{\sqrt{x}-1}+\dfrac{\sqrt{x}}{x-\sqrt{x}}\right):\dfrac{\sqrt{x}+1}{3}\)

\(=\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\cdot\dfrac{3}{\sqrt{x}+1}\)

\(=\dfrac{3}{\sqrt{x}+1}\)

b) Để P=1 thì \(\sqrt{x}+1=3\)

hay x=4(thỏa ĐK)