Question 306372
4. 4x2 + 20x + 5y +xy
Reordering:
4x^2+xy + 20x + 5y
Grouping:
(4x^2+xy) + (20x + 5y)
x(4x+y) + 5(4x + y)
(4x + y)(x+5)
.
7. 48x2y + 20xz +12xy + 5z 
Reordering:
48x^2y+12xy + 20xz+5z
Grouping:
(48x^2y+12xy) + (20xz+5z)
12xy(4x+1) + 5z(4x+1)
(4x+1)(12xy+5z)