The solutions are:
x
=
−
4
,
x
=
7
Explanation:
x
2
−
3
x
−
28
=
0
We can first factorise this expression by splitting the middle term and then find the solutions:
=
x
2
−
7
x
+
4
x
−
28
=
0
=
x
(
x
−
7
)
+
4
(
x
−
7
)
=
0
=
(
x
+
4
)
(
x−
7
)
Now, we can equate the two factors with zero and find the solutions:
x
+
4
=
0
,
x
=
−
4
x−
7=
0
,
x
=
7
