(2x+5)(x-3) Firstly, consider the first term. Since it's
2
x
2
, there are only two linear factors that it can be 'broken down' into:
x
and
2
x
. Thus we can re-write the expression
2
x
2
−
x
−
15
as
(
2
x
+
a
)
(
x
+
b
)
where
a
and
b
are real numbers to be determined