A=\(\dfrac{1}{6ab}.6a^2.b\)
=a
B=\(\sqrt{x}-2+\sqrt{x}-3\)
=\(2\sqrt{x}-5\)
\(A=\dfrac{1}{6ab}\sqrt{36.a^4b^2}=\dfrac{1}{6ab}.6a^2b=a\)
B=\(\dfrac{\left(\sqrt{x}-2\right)^2}{\sqrt{x}-2}-\dfrac{\left(\sqrt{x}+3\right)\left(3-\sqrt{x}\right)}{\sqrt{x}+3}\)
=\(\sqrt{x}-2-3+\sqrt{x}\)
\(=2\sqrt{x}-5\)