Rút gọn: a) x - y/√x - √y; b) (x√x - y√y/√x - √y) - x - √xy; c) (x√x + y√y/x - √xy + y) - √x + √y

giai pt
a)√x -√4x +√9x
b)can tat ca x-1 -can tat ca 4x-4 -can tat ca 9x-9=9-7*can tat ca x-1
c)3*căn tất cả 9x+18 - 2*can tat ca 4x+8= can tat ca 16x+32
rut g0n
a)x-y/√x- √y
b)(x√x -y√y/ √x-√y)-x-√xy
c) (x√x+y√y/x- √xy+y) -√x +√ y