(
x
+
2
)
(
x
-
2
)
=
____________________
-
____________________
(
x
+
2
)
(
____________________
+
2
)
=
x^2
+
4x
+
____________________
(
4
+
2a
)
(
4
+
____________________
)
=
____________________
+
____________________
+
6a^2
(
7a
+
2b
)
(
____________________
-
5b
)
=
49a^2
-
21ab
-
____________________
(
-
3a
+
5b
)
(
-
3a
-
5b
)
=
____________________
-
25b^
2
