[tex]2\sqrt{15^2}=2\cdot15=30\\\\\\2\sqrt{15^2}=2\cdot\left(15^2\right)^\frac{1}{2}=2\cdot15^{2\cdot\frac{1}{2}}=2\cdot15=30[/tex]
[tex]\left(2\sqrt{15}\right)^2=2^2\cdot\left(\sqrt{15}\right)^2=4\cdot15=60\\\\\left(2\sqrt{15}\right)^2=2^2\cdot\left(\sqrt{15}\right)^2=4\cdot\left(15^\frac{1}{2}\right)^2=4\cdot15^{\frac{1}{2}\cdot2}=4\cdot15^1=4\cdot15=60[/tex]
