Simplify the surd expression. Simplify the surd.
$(2\sqrt 3 + 3\sqrt 2)^2$
I know I should us this formula: $(a^2+2ab+b^2)$
But this gets complicated later. Please explain. :(
 A: Applying the formula you get
$$(2\sqrt3+3\sqrt2)^2 = 4\cdot3 + 2\cdot 2\sqrt3\cdot 3\sqrt 2 + 9\cdot 2 = 30 + 12\sqrt6$$
A: Alternatively, with a little simplification:
$$(2\sqrt{3}+3\sqrt{2})=(\sqrt{2}\sqrt{2}\sqrt{3}+\sqrt{3}\sqrt{3}\sqrt{2})=(\sqrt{2}(\sqrt{2}\sqrt{3}+\sqrt{3}\sqrt{3}))=\sqrt{2}(\sqrt{6}+3)$$
we can find the result:
$$\begin{align}[\sqrt{2}(\sqrt{6}+3)]^2&=2(\sqrt{6}+3)^2\\ & =2(6+2\sqrt{6}\cdot3+3^2) \\ &=2(15+6\sqrt{6}) \\ &=30+12\sqrt{6}
\end{align}$$
A: We are given: 
$$(2\sqrt 3 + 3\sqrt 2)^2$$
Expand:
$$(2\sqrt 3 + 3\sqrt 2)(2\sqrt 3 + 3\sqrt 2)$$
Multiply using techniques such as the FOIL method:
$$(2\sqrt 3 + 3\sqrt 2)(2\sqrt 3 + 3\sqrt 2)=4\sqrt9+6\sqrt6+6\sqrt6+9\sqrt4$$
Simplify:
$$4(3)+12\sqrt6+9(2)\\=12+18+12\sqrt6\\=30+12\sqrt6$$
A: Without any formula try to calculate:
$$
(2\sqrt {3} + 3\sqrt{2})^2 = (2\sqrt {3} + 3\sqrt{2}) \cdot (2\sqrt {3} + 3\sqrt{2})
$$
But it seems like a lot computing, can not it be simplified a bit? Yes, it can. The answer is in the formula you wrote, because:
Edit after @Zado comment:
$$
(a+b)^2=(a+b)\cdot (a+b)=a^2 + ab + ba +b^2
$$
But since multiplication ($\cdot$) is commutative that is
$$ab=ba$$
we can easier the formula even a little bit more to the final form
$$
 (a+b)^2 = \ldots = a^2 + 2ab + b^2
$$
Now it is a bit easier to do the computing, because you can put $a = 2\sqrt{3}$ and $b = 3\sqrt{2}$ and then use the formula.
