展开 ((3x-L)(L+3x))/(18)

解答

展开

\frac{( 3 x - L ) ( L + 3 x )}{18}

\frac{x ^{2}}{2} - \frac{L ^{2}}{18}

求解步骤

\frac{( 3 x - L ) ( L + 3 x )}{18}

乘开

(3 x - L) (L + 3 x) : 9 x^{2} - L^{2}

= \frac{9 x ^{2} - L ^{2}}{18}

使用分式法则:

\frac{a \pm b}{c} = \frac{a}{c} \pm \frac{b}{c}

\frac{9 x ^{2} - L ^{2}}{18} = \frac{9 x ^{2}}{18} - \frac{L ^{2}}{18}

= \frac{9 x ^{2}}{18} - \frac{L ^{2}}{18}

消掉

\frac{9 x ^{2}}{18} : \frac{x ^{2}}{2}

= \frac{x ^{2}}{2} - \frac{L ^{2}}{18}

e x p an d (x^{3} - 1) 3 x^{2} - 2 x

e x p an d \frac{( 1 + x ) ^{2}}{2}

\frac{d ^{2}}{d k ^{2}} ((x) (e^{2 x} - k x))

e x p an d (- 1 - x) \cdot (- 4 - y) - (- x) \cdot (- y)

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