Question 122586
4x^2 + 20x + 5y +xy 
=4x^2+20x+xy+5y
=4x(x+5)+y(x+5)
=(4x+y)(x+5)
.
48x^2y + 20xz +12xy + 5z 
48x^2y+12xy+20xz+5z
12xy(4x+1)+5x(4x+1)
(12xy+5x)(4x+1)
.
Ed