x既2次=12-x

x^2 + x -12 =0
(x -3)(x + 4) = 0
x = 3 or x = -4

x^2 = 12 -x
x^2 + x -12 =0
(x-3)(x+4)=0

li D 叫做 quadratic equations. 首先要將條式寫成 ax^2 +bx+c=0 一定要寫成li個樣先做到落去=] 然後做factorization就可以啦 ^^ 希望幫到你

2007-11-21 22:36:33 補充：
遺留了/// x=3 or x = -4^ ^

x=0掛
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