平方完成

$\begin{array}{l} ax^2 + bx + c \\ = a\left( {x^2 + \frac{b}{a}x} \right) + c \\ = a\left( {x + \frac{b}{{2a}}} \right)^2 - \frac{{b^2 }}{{4a}} + c \\ = a\left( {x + \frac{b}{{2a}}} \right)^2 - \frac{{b^2 - 4ac}}{{4a}} \\ \end{array}$

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[索引トップ]

by数学ナビゲーター