(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]
=4x-2y-z-5x[6y-(x+y)]+x-(3y-10z)
=4x-2y-z-30xy+5x²+5xy+x-3y+10z
=5x-5y+9z-25xy+5x²