1) 2(a³+27)= 2(a+3)(a²-3a+9)
2) (4x-y)²+3(4x-y)= (4x-y)(4x-y+3)
3) (m+n)²+2(m+n)+1= (m+n+1)²= (m+n+1)(m+n+1)
