giải pt
1. \(x^2-5x+14=4\sqrt{x+1}\)
2. \(x^4+x^2+1=y^2\)với x, y nguyên
3. \(xy-2x+3y=21\)
4. \(x=\sqrt{x-\frac{1}{x}}+\sqrt{1-\frac{1}{x}}\)
5. \(\frac{36}{\sqrt{x-2}}+\frac{4}{\sqrt{y-1}}=28-4\sqrt{x-2}-\sqrt{y-1}\)
6. \(2\left(x^2+2x+3\right)=5\sqrt{x^3+3x^2+3x+2}\)