Home
Random
Log in
Settings
Donate
About Wikiversity
Disclaimers
Search
Đẳng thức đại số
Language
Watch
Edit
a
2
−
b
2
=
(
a
+
b
)
(
a
−
b
)
{\displaystyle a^{2}-b^{2}=(a+b)(a-b)}
(
a
+
b
)
(
a
−
b
)
=
a
2
+
a
b
−
a
b
+
b
2
=
a
2
−
b
2
{\displaystyle (a+b)(a-b)=a^{2}+ab-ab+b^{2}=a^{2}-b^{2}}
(
a
+
b
)
2
=
a
2
+
2
a
b
+
b
2
{\displaystyle (a+b)^{2}=a^{2}+2ab+b^{2}}
(
a
+
b
)
2
=
(
a
+
b
)
(
a
+
b
)
=
a
2
+
a
b
+
a
b
+
b
2
=
a
2
+
2
a
b
+
b
2
{\displaystyle (a+b)^{2}=(a+b)(a+b)=a^{2}+ab+ab+b^{2}=a^{2}+2ab+b^{2}}
(
a
−
b
)
2
=
a
2
−
2
a
b
+
b
2
{\displaystyle (a-b)^{2}=a^{2}-2ab+b^{2}}
(
a
−
b
)
2
=
(
a
−
b
)
(
a
−
b
)
=
a
2
−
a
b
−
a
b
+
b
2
=
a
2
−
2
a
b
+
b
2
{\displaystyle (a-b)^{2}=(a-b)(a-b)=a^{2}-ab-ab+b^{2}=a^{2}-2ab+b^{2}}
a
2
+
b
2
=
(
a
2
−
b
2
)
+
2
a
b
=
(
a
2
+
b
2
)
−
2
a
b
{\displaystyle a^{2}+b^{2}=(a^{2}-b^{2})+2ab=(a^{2}+b^{2})-2ab}
