Answer:
Let's say that
f
(
x
)
=
x
2
−
10
The graph below shows
y
=
f
(
x
)
:
graph{x^2-10 [-6, 6, -15, 15]}
When we want
f
(
x
)
>
0
, we want
y
>
0
, or all the values of
x
where
f
(
x
)
>
0
.
In this instance,
x
2
−
10
>
0
x
2
>
10
x
>
√
10
x
<
−
√
10
Proof:
x=10:
10
2
−
10
=
100
−
10
=
90
x=6
6
2
−
10
=
36
−
10
=
26
x=1:
1
2
−
10
=
1
−
10
=
−
9
x=-1:
(
−
1
)
2
−
10
=
1
−
10
=
−
9
x=-6
(
−
6
)
2
−
10
=
36
−
10
=
26
x=-10:
(
−
10
)
2
−
10
=
100
−
10
=
90
