두뇌 스트레칭
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COMMON MATH 1
곱셈공식 · 인수분해 공식 등호 뒤 빈칸 정리
학생들이 공식을 직접 떠올리며 쓸 수 있도록, 등호 뒤를 비워 둔 암기용 정리 페이지입니다.
출처 · 자료 제작: 두뇌스트레칭
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1. 곱셈공식
1
)
(
a
+
b
)
2
=
1)\ (a+b)^2=
1
)
(
a
+
b
)
2
=
2
)
(
a
−
b
)
2
=
2)\ (a-b)^2=
2
)
(
a
−
b
)
2
=
3
)
(
a
+
b
)
(
a
−
b
)
=
3)\ (a+b)(a-b)=
3
)
(
a
+
b
)
(
a
−
b
)
=
4
)
(
x
+
a
)
(
x
+
b
)
=
4)\ (x+a)(x+b)=
4
)
(
x
+
a
)
(
x
+
b
)
=
5
)
(
a
x
+
b
)
(
c
x
+
d
)
=
5)\ (ax+b)(cx+d)=
5
)
(
a
x
+
b
)
(
c
x
+
d
)
=
6
)
(
x
+
a
)
(
x
+
b
)
(
x
+
c
)
=
6)\ (x+a)(x+b)(x+c)=
6
)
(
x
+
a
)
(
x
+
b
)
(
x
+
c
)
=
7
)
(
x
−
a
)
(
x
−
b
)
(
x
−
c
)
=
7)\ (x-a)(x-b)(x-c)=
7
)
(
x
−
a
)
(
x
−
b
)
(
x
−
c
)
=
8
)
(
a
+
b
+
c
)
2
=
8)\ (a+b+c)^2=
8
)
(
a
+
b
+
c
)
2
=
9
)
(
a
b
+
b
c
+
c
a
)
2
=
9)\ (ab+bc+ca)^2=
9
)
(
ab
+
b
c
+
c
a
)
2
=
10
)
(
a
+
b
)
3
=
10)\ (a+b)^3=
10
)
(
a
+
b
)
3
=
11
)
(
a
−
b
)
3
=
11)\ (a-b)^3=
11
)
(
a
−
b
)
3
=
12
)
(
a
2
+
a
b
+
b
2
)
(
a
2
−
a
b
+
b
2
)
=
12)\ (a^2+ab+b^2)(a^2-ab+b^2)=
12
)
(
a
2
+
ab
+
b
2
)
(
a
2
−
ab
+
b
2
)
=
13
)
(
x
2
+
x
+
1
)
(
x
2
−
x
+
1
)
=
13)\ (x^2+x+1)(x^2-x+1)=
13
)
(
x
2
+
x
+
1
)
(
x
2
−
x
+
1
)
=
2. 인수분해 공식
1
)
a
2
+
2
a
b
+
b
2
=
1)\ a^2+2ab+b^2=
1
)
a
2
+
2
ab
+
b
2
=
2
)
a
2
−
2
a
b
+
b
2
=
2)\ a^2-2ab+b^2=
2
)
a
2
−
2
ab
+
b
2
=
3
)
x
2
+
(
a
+
b
)
x
+
a
b
=
3)\ x^2+(a+b)x+ab=
3
)
x
2
+
(
a
+
b
)
x
+
ab
=
4
)
a
c
x
2
+
(
a
d
+
b
c
)
x
+
b
d
=
4)\ acx^2+(ad+bc)x+bd=
4
)
a
c
x
2
+
(
a
d
+
b
c
)
x
+
b
d
=
5
)
a
2
−
b
2
=
5)\ a^2-b^2=
5
)
a
2
−
b
2
=
6
)
a
3
+
b
3
=
6)\ a^3+b^3=
6
)
a
3
+
b
3
=
7
)
a
3
−
b
3
=
7)\ a^3-b^3=
7
)
a
3
−
b
3
=
8
)
a
2
+
b
2
+
c
2
+
2
a
b
+
2
b
c
+
2
c
a
=
8)\ a^2+b^2+c^2+2ab+2bc+2ca=
8
)
a
2
+
b
2
+
c
2
+
2
ab
+
2
b
c
+
2
c
a
=
9
)
a
4
+
a
2
b
2
+
b
4
=
9)\ a^4+a^2b^2+b^4=
9
)
a
4
+
a
2
b
2
+
b
4
=
10
)
x
4
+
x
2
+
1
=
10)\ x^4+x^2+1=
10
)
x
4
+
x
2
+
1
=
11
)
a
3
+
b
3
+
c
3
−
3
a
b
c
=
11)\ a^3+b^3+c^3-3abc=
11
)
a
3
+
b
3
+
c
3
−
3
ab
c
=
12
)
a
3
+
b
3
+
c
3
−
3
a
b
c
=
12)\ a^3+b^3+c^3-3abc=
12
)
a
3
+
b
3
+
c
3
−
3
ab
c
=
3. 변형공식
1
)
(
a
+
b
)
2
=
1)\ (a+b)^2=
1
)
(
a
+
b
)
2
=
2
)
(
a
−
b
)
2
=
2)\ (a-b)^2=
2
)
(
a
−
b
)
2
=
3
)
a
2
+
b
2
=
3)\ a^2+b^2=
3
)
a
2
+
b
2
=
4
)
a
2
+
b
2
=
4)\ a^2+b^2=
4
)
a
2
+
b
2
=
5
)
a
2
+
1
a
2
=
5)\ a^2+\frac{1}{a^2}=
5
)
a
2
+
a
2
1
=
6
)
a
2
+
1
a
2
=
6)\ a^2+\frac{1}{a^2}=
6
)
a
2
+
a
2
1
=
7
)
(
a
+
1
a
)
2
=
7)\ \left(a+\frac{1}{a}\right)^2=
7
)
(
a
+
a
1
)
2
=
8
)
a
3
+
b
3
=
8)\ a^3+b^3=
8
)
a
3
+
b
3
=
9
)
a
3
−
b
3
=
9)\ a^3-b^3=
9
)
a
3
−
b
3
=
10
)
a
3
+
1
a
3
=
10)\ a^3+\frac{1}{a^3}=
10
)
a
3
+
a
3
1
=
11
)
a
3
−
1
a
3
=
11)\ a^3-\frac{1}{a^3}=
11
)
a
3
−
a
3
1
=
12
)
a
2
+
b
2
+
c
2
+
a
b
+
b
c
+
c
a
=
12)\ a^2+b^2+c^2+ab+bc+ca=
12
)
a
2
+
b
2
+
c
2
+
ab
+
b
c
+
c
a
=
13
)
a
2
+
b
2
+
c
2
−
a
b
−
b
c
−
c
a
=
13)\ a^2+b^2+c^2-ab-bc-ca=
13
)
a
2
+
b
2
+
c
2
−
ab
−
b
c
−
c
a
=
14
)
a
2
+
b
2
+
c
2
=
14)\ a^2+b^2+c^2=
14
)
a
2
+
b
2
+
c
2
=
15
)
a
3
+
b
3
+
c
3
=
15)\ a^3+b^3+c^3=
15
)
a
3
+
b
3
+
c
3
=
4. 추가로 알아두면 좋은 공식
1
)
x
5
+
y
5
=
1)\ x^5+y^5=
1
)
x
5
+
y
5
=
2
)
x
7
+
y
7
=
2)\ x^7+y^7=
2
)
x
7
+
y
7
=
3
)
x
6
+
y
6
=
3)\ x^6+y^6=
3
)
x
6
+
y
6
=
4
)
x
6
+
y
6
=
4)\ x^6+y^6=
4
)
x
6
+
y
6
=
5
)
a
4
−
b
4
=
5)\ a^4-b^4=
5
)
a
4
−
b
4
=
6
)
a
5
−
b
5
=
6)\ a^5-b^5=
6
)
a
5
−
b
5
=
7
)
a
n
−
b
n
=
7)\ a^n-b^n=
7
)
a
n
−
b
n
=
8
)
x
4
−
1
=
8)\ x^4-1=
8
)
x
4
−
1
=
9
)
x
5
−
1
=
9)\ x^5-1=
9
)
x
5
−
1
=
10
)
x
n
−
1
=
10)\ x^n-1=
10
)
x
n
−
1
=
11
)
(
a
+
b
+
c
+
d
)
2
=
11)\ (a+b+c+d)^2=
11
)
(
a
+
b
+
c
+
d
)
2
=
12
)
(
a
+
b
+
c
+
d
+
e
)
2
=
12)\ (a+b+c+d+e)^2=
12
)
(
a
+
b
+
c
+
d
+
e
)
2
=
13
)
(
a
+
b
+
c
+
d
+
e
+
⋯
+
z
)
2
=
13)\ (a+b+c+d+e+\cdots+z)^2=
13
)
(
a
+
b
+
c
+
d
+
e
+
⋯
+
z
)
2
=