展開整理再解方程式

(x -1)² + x² + (x + 1)² = 110
(x² - 2x + 1) + x² + (x² + 2x + 1) = 110
x² - 2x + 1 + x² + x² + 2x + 1 = 110
3x² + 2 = 110
3x² - 108 = 0
x² - 36 = 0
x² - 6² = 0
(x + 6)(x - 6) = 0
x + 6 = 0 或 x - 6 = 0
x = -6 或 x = 6


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x² - (x - 2)² = (x - 4)²
x² - (x² - 4x + 4) = x² -8x + 16
x² - x² + 4x - 4 = x² -8x + 16
-x² + 12x - 20 = 0
x² - 12x + 20 = 0
(x - 2)(x - 10) = 0
x - 2 = 0 或 x - 10 = 0
x= 2 或 x = 10

(X-1) 2+x2+(x+1)2=110
(X^2 -2X+1)+ X^2 +(X^2 +2X+1)=110
3X^2+2 =110
3X^2=108
X^2=36
X=6或-6

x2-(x-2)2=(x-4)2
展開整理
X^2-12X+20=0
(X-2)(X-10)=0
X=2或10
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