If you have four terms without a common factor you need to group them.
Grouping like this (4+5xy)+(-10y-2x)(4+5xy)+(−10y−2x) achieves little.
Group the terms differently:
(4-2x)+(5xy-10y)" "larr(4−2x)+(5xy−10y) ← find the HCF of each bracket
=2(2-x) color(blue)(+5y(x-2))" "larr=2(2−x)+5y(x−2) ← divide -1−1 out as a factor
=2(2-x)-5y(-x+2)" "larr=2(2−x)−5y(−x+2) ← the signs change
2(2-x)-5y(2-x)" "larr2(2−x)−5y(2−x) ← makes equal brackets
(2-x)(2-5y)" "larr(2−x)(2−5y) ← there are two factor
OR:
(4-10y) +(-2x+5xy)(4−10y)+(−2x+5xy)
=2(2-5y)+x(-2+5y)=2(2−5y)+x(−2+5y)
=2(2-5y)-x(2-5y)=2(2−5y)−x(2−5y)
=(2-5y)(2-x)=(2−5y)(2−x)
