Question 872713
-60z^5 + 65z^4 + 20z^3 
-5z^3(12z^2 -13z -4)
now factor the expression within parenthesis, start by finding the prime factors of 4 and 12
4 = 2^2 * 1 and 12 = 3*2^2
for 12, I will try 3 and 4 and for 4, I will try 4 and 1
(3z - 4)(4z + 1) = 12z^2 -13z -4
therefore
-60z^5 + 65z^4 + 20z^3 = -5z^3(3z - 4)(4z + 1)