Solve for $a$: $$\sqrt{4+\sqrt{16+16a}}+ \sqrt{1+\sqrt{1+a}} = 6.$$
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Solve for $a$: $$\sqrt{4+\sqrt{16+16a}}+ \sqrt{1+\sqrt{1+a}} = 6.$$
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
8
Solve for $a$: $$\sqrt{4+\sqrt{16+16a}}+ \sqrt{1+\sqrt{1+a}} = 6.$$
train