$$= 15 ( 3 + 4 \sqrt { 5 } + 1 ) - 10 ( 9 + 4 \sqrt { 5 } + 4 \sqrt { 5 } ) + 9$$
$-20\sqrt{5}-21\approx -65.72135955$
$$15\left(4+4\sqrt{5}\right)-10\left(9+4\sqrt{5}+4\sqrt{5}\right)+9$$
$$60+60\sqrt{5}-10\left(9+4\sqrt{5}+4\sqrt{5}\right)+9$$
$$60+60\sqrt{5}-10\left(9+8\sqrt{5}\right)+9$$
$$60+60\sqrt{5}-90-80\sqrt{5}+9$$
$$-30+60\sqrt{5}-80\sqrt{5}+9$$
$$-30-20\sqrt{5}+9$$
$$-21-20\sqrt{5}$$
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