(6)平方型の展開(解答) 学習日    月    日(   )
 乗法公式 4(平方型の展開)       (x+3)2
  =x2+2・3x+32
  =x2+6x+9
  (x±a)2=x2±2ax+a2   
 
       2倍  2乗
 
乗法公式を使って,次の式を展開しなさい。 
1  (x+2)2 = x2+4x+4
 
2  (x−5)2 = x2−10x+25
  
3  (x+4)2 = x2+8x+16
  
4  (x−6)2 = x2−12x+36
  
5  (x+1)2 = x2+2x+1
  
6  (x−8)2 = x2−16x+64
  
7  (x+3)2 = x2+6x+9
 
8  (x−9)2 = x2−18x+81
 
9  (x+7)2 = x2+14x+49
  
10  (x−)2 = x2−x+
  
11  (a+0.2)2 = a2+0.4a+0.04
  
12  (y−10)2 = y2−20y+100
  
13  (x+y)2 = x2+2xy+y2
  
14  (x−2y)2 = x2−4xy+4y2
  
15  (a+3b)2 = a2+6ab+9b2
 
16  (a−6b)2 = a2−12ab+36b2
 
17  (2x−1)2 = (2x)2−2(2x)+1
  = 4x2−4x+1
  
18  (3x+y)2 = (3x)2−2(3x)y+y2
  = 9x2+6xy+y2
  
19  (5−x)2 = 52−2・5・x+x2
  =25−10x+x2= x2−10x+25
  
20  (2x+7y)2 = (2x)2+2(2x)・(7y)+(7y)2
  = 4x2+28xy+49y2
  

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