Verified answer

12p²+3ay-4y-a = (4p-a)(3p+1y) - 3y

5x³a+8y-10x²-4ayx = (x-a)(5x²-2ay)-(2x-8)

(x+y)²-x-y = (x+y-1)(x+y)-1

3a-4c-(4c-3a)² = - (4c-3a+3)(4c-3a-1)

(m-n)²-mk+kn = (m-n-k)(m-n+k)+kn