Answer
$2Al(OH)_3(s)+3H_2SO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+6H_2O(l)$
Work Step by Step
$Al(OH)_3(s)+H_2SO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+H_2O(l)$
Add a coefficient of 2 to $Al(OH)_3$ to balance $Al$.
Add a coefficient of 3 to $H_2SO_4$ to balance $S$.
$2Al(OH)_3(s)+3H_2SO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+H_2O(l)$
Add a coefficient of 6 to $H_2O$ to balance $H$ and $O$.
$2Al(OH)_3(s)+3H_2SO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+6H_2O(l)$