Answer:
[tex]\large\boxed{\sqrt{27y^8}=3y^4\sqrt3}[/tex]
Step-by-step explanation:
[tex]\sqrt{27y^8}=\sqrt{9\cdot3\cdot y^{4\cdot2}}\\\\\text{Use}\ \sqrt{ab}=\sqrt{a}\cdot\sqrt{b},\ (a^n)^m=a^{nm}\ \text{and}\ \sqrt{a^2}=a\\\\=\sqrt9\cdot\sqrt3\cdot\sqrt{(y^4)^2}=3\cdot\sqrt3\cdot y^4=3y^4\sqrt3[/tex]
