Rewrite
25
b
2
as
(
5
b
)
2
.
(
5
b
)
2
−
60
b
+
36
Rewrite
36
as
6
2
.
(
5
b
)
2
−
60
b
+
6
2
Check the middle term by multiplying
2
a
b
and compare this result with the middle term in the original expression.
2
a
b
=
2
⋅
(
5
b
)
⋅
−
6
Simplify.
2
a
b
=
−
60
b
Factor using the perfect square trinomial rule
a
2
−
2
a
b
+
b
2
=
(
a
−
b
)
2
, where
a
=
5
b
and
b
=
−
6
.
(
5
b
−
6
)
2
