a: \(2\sqrt{50}-3\cdot\sqrt{75}-4\cdot\sqrt{98}+2\cdot\sqrt{108}\)
\(=2\cdot5\sqrt2-3\cdot5\sqrt3-4\cdot7\sqrt2+2\cdot6\sqrt3\)
\(=10\sqrt2-15\sqrt3-28\sqrt2+12\sqrt3=-18\sqrt2-3\sqrt3\)
b: \(\sqrt{17-12\sqrt2}-\sqrt{\left(2\sqrt2-5\right)^2}\)
\(=\sqrt{\left(3-2\sqrt2\right)^2}-\left|2\sqrt2-5\right|\)
\(=3-2\sqrt2-\left(5-2\sqrt2\right)=3-2\sqrt2-5+2\sqrt2=3-5=-2\)
c: \(\frac{3-\sqrt3}{1-\sqrt3}+\frac{3}{2\sqrt2+3}-\frac{4}{\sqrt2}\)
\(=-\frac{\sqrt3\left(\sqrt3-1\right)}{\sqrt3-1}+\frac{3\left(3-2\sqrt2\right)}{\left(3-2\sqrt2\right)\left(3+2\sqrt2\right)}-2\sqrt2\)
\(=-\sqrt3+3\left(3-2\sqrt2\right)-2\sqrt2=-\sqrt3+9-6\sqrt2-2\sqrt2=9-\sqrt3-8\sqrt2\)
Cho 3 số dương a,b,c thỏa mãn a+b+c=1. CMR:
