Factor $12=2^{2}\times 3$. Rewrite the square root of the product $\sqrt{2^{2}\times 3}$ as the product of square roots $\sqrt{2^{2}}\sqrt{3}$. Take the square root of $2^{2}$.
Factor $12=2^{2}\times 3$. Rewrite the square root of the product $\sqrt{2^{2}\times 3}$ as the product of square roots $\sqrt{2^{2}}\sqrt{3}$. Take the square root of $2^{2}$.
$$-8\sqrt{3}+20+7\times 2\sqrt{3}-17\sqrt{16}$$
Multiply $7$ and $2$ to get $14$.
$$-8\sqrt{3}+20+14\sqrt{3}-17\sqrt{16}$$
Combine $-8\sqrt{3}$ and $14\sqrt{3}$ to get $6\sqrt{3}$.
