Rút gọn:
\(a,A=\sqrt{9\left(a+b\right)}-2\sqrt{16\left(a+b\right)}-3\sqrt{a+b}+\frac{1}{5}\sqrt{25\left(a+b\right)}\)
\(b,B=\frac{2ab\sqrt{a}}{\sqrt{a}+\sqrt{b}}+\frac{2ab\sqrt{b}}{\sqrt{a}+\sqrt{b}}\)
\(c,C=\frac{2ab}{a+\sqrt{ab}}+\frac{2ab}{b+\sqrt{ab}}\)
\(d,D=\frac{\frac{2ab\sqrt{a}}{\sqrt{a}+\sqrt{b}}+\frac{2ab\sqrt{b}}{\sqrt{a}+\sqrt{b}}}{\frac{2ab}{a+\sqrt{ab}}+\frac{2ab}{b+\sqrt{ab}}}\)
Giúp mình với.Thanks
cho anh tao đê
a,A= -7\(\sqrt{a+b}\)
a) \(A=\sqrt{9\left(a+b\right)}-2\sqrt{16\left(a+b\right)}-3\sqrt{a+b}+\frac{1}{5}\sqrt{25\left(a+b\right)}\)
\(A=3\sqrt{a+b}-8\sqrt{a+b}-3\sqrt{a+b}+\sqrt{a+b}\)
\(A=-7\sqrt{a+b}\)
b) ĐKXĐ : \(\hept{\begin{cases}\sqrt{a}+\sqrt{b}\ne0\\a\ge0\\b\ge0\end{cases}}\Leftrightarrow a\ne-b\ne0\)
\(B=\frac{2ab\sqrt{a}}{\sqrt{a}+\sqrt{b}}+\frac{2ab\sqrt{b}}{\sqrt{a}+\sqrt{b}}\)
\(B=\frac{2ab\sqrt{a}+2ab\sqrt{b}}{\sqrt{a}+\sqrt{b}}=\frac{2ab\left(\sqrt{a}+\sqrt{b}\right)}{\sqrt{a}+\sqrt{b}}\)
c,C=2\(\sqrt{ab}\)
D=\(\sqrt{ab}\)