x2
?
16y2
=
(
x
+
____________________
)
(
____________________
?
4y
)
;
9m2
?
n2
=
(
____________________
+
n
)
(
____________________
?
n
)
;
x6
?
196
=
(
x3
+
____________________
)
(
____________________
?
14
)
49a2
?
81b2
=
(
____________________
+
9b
)
(
____________________
?
9b
)
36x4
?
25y4
=
(
6x
+
____________________
)
(
6x
?
____________________
)
