Rút gọn rồi tính: 2 căn((-5)^6) + 3 căn((-2)^8)

* Hướng dẫn giải

$$\begin{gathered} 2\sqrt{{\left(-5\right)}^6}+3\sqrt{{\left(-2\right)}^8} \\ =2.\sqrt{{\left[{\left(-5\right)}^3\right]}^2}+3.\sqrt{{\left[{\left(-2\right)}^4\right]}^2} \\ =2.\left|{\left(-5\right)}^3\right|+3.\left|{\left(-2\right)}^4\right| \\ =2.\left|-125\right|+3.\left|16\right| \\ =2.125+3.16=298 \end{gathered}$$