Cho x, y, z > 0 thoả mãn: x + y + z + √xyz = 4. Chứng minh √[x(4 - y)(4 - z)] + √[y(4 - x)(4 - z)] + √[z(4 - x)(4 - y) = 8 + √xyz

1. Cho x,y,z>0 thoả mãn: x+y+z+√xyz =4. CMR:
[x(4-y)(4-z)]+√[y(4-x)(4-z)]+√[z(4-x)(4-y) =8+√xyz
2. Cho x,y thoả mãn: [x+√(1+y^2)]*[y+√(1+x^2)] =1. CMR:
[x+√(1+x^2)]*[y+√(1+y^2)] =1