Answer:
Ste(x−5)2=x2−10x 25
step-by-step explanation:
The standard form of a polynomial in one variable is a sum of terms in decreasing order of degree.
For brevity, terms with negative coefficients are usually written as subtractions rather than adding the additive inverses. That is, we would write
x
2
−
3
x
+
2
rather than
x
2
+
(
−
3
)
x
+
2
In order to express
(
x
−
5
)
2
in standard form, we need to multiply it out, combining terms of like degree. We can use the FOIL mnemonic to help:
(
x
−
5
)
2
=
(
x
−
5
)
(
x
−
5
)
(
x
−
5
)
2
=
First
(
x
)
(
x
)
+
Outside
(
x
)
(
−
5
)
+
Inside
(
−
5
)
(
x
)
+
Last
(
−
5
)
(
−
5
)
(
x
−
5
)
2
=
x
2
−
5
x
−
5
x
+
25
(
x
−
5
)
2
=
x
2
−
10
x
+
25
Alternatively, we can recognise a pattern and use it.
For example:
(
a
+
b
)
2
=
a
2
+
2
a
b
+
b
2
(
a
−
b
)
2
=
a
2
−
2
a
b
+
b
2
So we could take the second of these and put
a
=
x
,
b
=
5
to find:
(
x
−
5
)
2
=
x
2
−
2
(
x
)
(
5
)
+
5
2
(
x
−
5
)
2
=
x
2
−
10
x
+
25
