Welcome to Westonci.ca, where finding answers to your questions is made simple by our community of experts. Connect with a community of professionals ready to provide precise solutions to your questions quickly and accurately. Explore comprehensive solutions to your questions from a wide range of professionals on our user-friendly platform.

What is the domain of the function?
X+6
f(x)=(x-7)(x+5)
A all real numbers except 7
Ball real numbers except 5 and -7
Call real numbers except -5 and 7
D all real numbers


Sagot :

I got a domain and range of:
(


,
5
)

(
5
,

)
, or
x

5
(


,
1
)

(
1
,

)
, or
y

1
The function is undefined for
x
values when the denominator,
x

5
, is
0
; it's undefined to divide by
0
. Therefore, when
x
=
5
,
f
(
x
)
is undefined.
f
(
5
)
=
5
+
7
5

5
=
12
0
Since the domain is based on the allowed values of
x
, the domain is:
(


,
5
)

(
5
,

)
Based on the domain, we would find the range by solving for
x
in terms of
f
(
x
)
, which we will write as
y
=
f
(
x
)
.
y
=
x
+
7
x

5
y
(
x

5
)
=
x
+
7
x
y

5
y
=
x
+
7
x

x
y
=

5
y

7
x
(
1

y
)
=

5
y

7
x
=

5
y

7
1

y
x
=
5
y
+
7
y

1
This means when
y
=
1
, the function is undefined as well. So, the range is:
(


,
1
)

(
1
,

)
You can see that this is the case in the graph itself:
graph{(x + 7)/(x - 5) [-73.3, 74.9, -37.07, 36.97]}
What you should notice is the horizontal asymptote at
y
=
1
, and the vertical asymptote at
x
=
5
.
Because the function is trying to reach an undefined value at those points (
x

5
,
y

1
), you get these "walls" that cannot be crossed, only ascended or descended from either side.