Đáp án:
\(\begin{array}{l}
a) - {a^3}\left( {b - 3} \right)\\
b)a - b\\
c)9a\\
d)10a
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)\sqrt {{a^6}.{{\left( {3 - b} \right)}^2}} \\
= {a^3}.\left| {3 - b} \right|\\
= - {a^3}\left( {b - 3} \right)\\
b)\dfrac{1}{a}.\sqrt {{a^2}{{\left( {a - b} \right)}^2}} \\
= \dfrac{1}{a}.\left| {a\left( {a - b} \right)} \right|\\
= \dfrac{1}{a}.a\left( {a - b} \right) = a - b\\
c)\sqrt {3a} .\sqrt {27a} \\
= 3\sqrt {3a} .\sqrt {3a} \\
= 3.\left| {3a} \right|\\
= 9a\\
d)5a - \sqrt {\dfrac{1}{{10}}} .\sqrt {250{a^2}} \\
= 5a - \sqrt {\dfrac{1}{{10}}} .5\sqrt {10{a^2}} \\
= 5a - 5\left| a \right|\\
= 5a + 5a = 10a
\end{array}\)
