Question

cứu e vs ạ ,e cần gấpppp

Answer 1

1:

a: \(A=\dfrac{x-2-9}{\sqrt{x-2}-3}=\sqrt{x-2}+3\)

\(=\sqrt{21-12\sqrt{3}}+3=2\sqrt{3}-3+3=2\sqrt{3}\)

b: \(B=\dfrac{2}{1-a}-\dfrac{a^2+2}{1-a^3}\)

\(=\dfrac{2a^2+2a+2-a^2-2}{1-a^3}=\dfrac{a^2+2a}{1-a^3}\)

\(=\dfrac{2+2\sqrt{2}}{1-2\sqrt{2}}=\dfrac{\sqrt{2}-3}{7}\)

f: \(F=\dfrac{3+\sqrt{1-a^2}}{\sqrt{1+a}}:\dfrac{3+\sqrt{1-a^2}}{\sqrt{1-a^2}}=\sqrt{1-a}\)

Khi \(a=\dfrac{\sqrt{3}}{2+\sqrt{3}}=-3+2\sqrt{3}\) thì \(F=\sqrt{1+3-2\sqrt{3}}=\sqrt{3}-1\)