These are a lot of problems. I feel like this may be copy-pasting from homework, but I will help you.
If you don't know how to simplify radicals, here's a site for you.
https://www.themathpage.com/alg/simplify-radicals.htm
Based on this, you can solve.
1) \(\sqrt{48}=\sqrt{4^2\times 3} = 4\sqrt3\)
2) \(\sqrt{90x^5y^6}=\sqrt{3^2\times2\times5\times x^5y^6}=3\sqrt{10\times x^4\times x\times y^6}=3x^2y^3\sqrt{10x}\)
3) \(\sqrt{\frac{49}{11}}=\frac{7}{\sqrt{11}}=\frac{7\sqrt{11}}{11}\)
I think you can do the next two.
So the answers are 3, 5
You can graph #2, on Desmos for example and find the roots.
1) \(x^2=64, \sqrt{x^2}=\sqrt{64}, x=8, x=-8\)
2) \(2x^2=72, x^2=36, \sqrt{x^2}=\sqrt{36}, x=6, x=-6\)
I think you can do the rest.
You are very welcome!
:P