Factorise the expressions and divide them as directed.
 
1. \((5p^2 - 25p + 20) \div (p - 1) =\)
 
2. \(4yz(z^2 + 6z - 16) \div 2y(z + 8) =\)
Answer variants:
\(5(p - 1)\)
\(5(p - 4)\)
\(2z(z + 8)\)
\(2z(z - 2)\)