\[\sqrt{a^2 \cdot (-a)^2} = \sqrt{a^2 \cdot a^2} = \sqrt{a^4} = a^2\]
\[\sqrt{a^6 \cdot (-a)^4} = \sqrt{a^6 \cdot a^4} = \sqrt{a^{10}} = |a^5|\]
\[\sqrt{a^6 \cdot (-a)^6} = \sqrt{a^6 \cdot a^6} = \sqrt{a^{12}} = |a^6| = a^6\]
\[\sqrt{a^2 \cdot (-a)^4} = \sqrt{a^2 \cdot a^4} = \sqrt{a^6} = |a^3|\]
Ответ: 1) a², 2) |a⁵|, 3) a⁶, 4) |a³|