Question

\(3\sqrt{9a^6}-3a^3\)

tính

Answer 1

\(3\sqrt{9a^6}-3a^3=3\left|3a^3\right|-3a^3\)

Xét \(a\ge0\Rightarrow3\left|3a^3\right|-3a^3=9a^3-3a^3=6a^3\)

Xét \(a< 0\Rightarrow3\left|3a^3\right|-3a^3=-9a^3-3a^3=-12a^3\)

Answer 2

\(3\sqrt{9a^6}-3a^3\)

\(=9a^3-3a^3\)

\(=6a^3\)