Simplify, using the laws of exponents. 5^(3/4) × 5^(1/4); (6^(1/3))⁶; 2^(1/2) × 18^(1/2)

$a^m a^n = a^{m+n}$, $(a^m)^n = a^{mn}$, $\dfrac{a^m}{a^n} = a^{m-n}$, $a^0 = 1$ and $a^{-n} = \dfrac{1}{a^n}$. $a^{1/n}$ is the $n$-th root of $a$, and $a^{m/n} = \left(\sqrt[n]{a}\right)^m$: take the root first.